X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=doc%2Ftinc.texi;h=dba075403dc4b7a62fa96e5bbf955681da16956e;hb=413faffca356b25cf69ddf0a718730d46f9941bc;hp=7d865053060513f9a2c395339fe32c59fce86d80;hpb=d0ea9c8ff287e879e531af9f1b52529421c0512f;p=tinc diff --git a/doc/tinc.texi b/doc/tinc.texi index 7d865053..8c8c7068 100644 --- a/doc/tinc.texi +++ b/doc/tinc.texi @@ -5,1170 +5,3401 @@ @setchapternewpage odd @c %**end of header +@include tincinclude.texi + @ifinfo +@dircategory Networking tools @direntry * tinc: (tinc). The tinc Manual. @end direntry -This is the info manual for tinc, a Virtual Private Network daemon. +This is the info manual for @value{PACKAGE} version @value{VERSION}, a Virtual Private Network daemon. -Copyright 1998 Ivo Timmermans +Copyright @copyright{} 1998-2015 Ivo Timmermans, +Guus Sliepen and +Wessel Dankers . - Permission is granted to make and distribute verbatim - copies of this manual provided the copyright notice and - this permission notice are preserved on all copies. +Permission is granted to make and distribute verbatim copies of this +manual provided the copyright notice and this permission notice are +preserved on all copies. - Permission is granted to copy and distribute modified - versions of this manual under the conditions for - verbatim copying, provided - that the entire resulting derived work is distributed - under the terms of a permission notice identical to this - one. +Permission is granted to copy and distribute modified versions of this +manual under the conditions for verbatim copying, provided that the +entire resulting derived work is distributed under the terms of a +permission notice identical to this one. @end ifinfo +@afourpaper +@paragraphindent none +@finalout + @titlepage @title tinc Manual @subtitle Setting up a Virtual Private Network with tinc -@author Ivo Timmermans +@author Ivo Timmermans and Guus Sliepen @page @vskip 0pt plus 1filll -Copyright @copyright{} 1998 Ivo Timmermans +This is the info manual for @value{PACKAGE} version @value{VERSION}, a Virtual Private Network daemon. - Permission is granted to make and distribute verbatim - copies of this manual provided the copyright notice and - this permission notice are preserved on all copies. +Copyright @copyright{} 1998-2015 Ivo Timmermans, +Guus Sliepen and +Wessel Dankers . - Permission is granted to copy and distribute modified - versions of this manual under the conditions for - verbatim copying, provided - that the entire resulting derived work is distributed - under the terms of a permission notice identical to this - one. +Permission is granted to make and distribute verbatim copies of this +manual provided the copyright notice and this permission notice are +preserved on all copies. + +Permission is granted to copy and distribute modified versions of this +manual under the conditions for verbatim copying, provided that the +entire resulting derived work is distributed under the terms of a +permission notice identical to this one. @end titlepage +@ifnottex @c ================================================================== -@node Top, Introduction, (dir), (dir) +@node Top +@top Top @menu -* Introduction:: Introduction -* Configuring a Linux system:: Before compiling tinc -* Installing tinc:: -* Configuring tinc:: -* Running tinc:: -* Technical information:: -* About us:: +* Introduction:: +* Preparations:: +* Installation:: +* Configuration:: +* Running tinc:: +* Controlling tinc:: +* Technical information:: +* Platform specific information:: +* About us:: * Concept Index:: All used terms explained @end menu +@end ifnottex @c ================================================================== -@node Introduction, Configuring a Linux system, Top, Top +@node Introduction @chapter Introduction -@c straight from the www page - -tinc is a Virtual Private Network (VPN) daemon that uses tunneling and +@cindex tinc +Tinc is a Virtual Private Network (VPN) daemon that uses tunneling and encryption to create a secure private network between hosts on the Internet. Because the tunnel appears to the IP level network code as a normal network device, there is no need to adapt any existing software. - -This tunneling allows VPN sites to share information with each other +The encrypted tunnels allows VPN sites to share information with each other over the Internet without exposing any information to others. -This document is the manual for tinc. Included are chapters on how to +This document is the manual for tinc. Included are chapters on how to configure your computer to use tinc, as well as the configuration process of tinc itself. @menu -* VPNs:: Virtual Private Networks in general -* tinc:: about tinc +* Virtual Private Networks:: +* tinc:: About tinc +* Supported platforms:: @end menu @c ================================================================== -@node VPNs, tinc, Introduction, Introduction +@node Virtual Private Networks @section Virtual Private Networks +@cindex VPN A Virtual Private Network or VPN is a network that can only be accessed -by a few elected computers that participate. This goal is achievable in +by a few elected computers that participate. This goal is achievable in more than just one way. @cindex private -For instance, a VPN can consist of a single stand-alone ethernet LAN. Or -even two computers hooked up using a null-modem cable@footnote{Though -discuss-able, I think it qualifies as a VPN.}. In these cases, it is -obvious that the network is @emph{private}. But there is another type -of VPN, the type tinc was made for. +Private networks can consist of a single stand-alone Ethernet LAN. Or +even two computers hooked up using a null-modem cable. In these cases, +it is +obvious that the network is @emph{private}, no one can access it from the +outside. But if your computers are linked to the Internet, the network +is not private anymore, unless one uses firewalls to block all private +traffic. But then, there is no way to send private data to trusted +computers on the other end of the Internet. @cindex virtual -tinc uses normal IP datagrams to encapsulate data that goes over the VPN -network link. In this case it's also clear that the network is -@emph{virtual}, because no direct network link has to exist between to -participants. - -As is the case with either type of VPN, anybody could eavesdrop. Or -worse, alter data. Hence it's probably advisable to encrypt the data +This problem can be solved by using @emph{virtual} networks. Virtual +networks can live on top of other networks, but they use encapsulation to +keep using their private address space so they do not interfere with +the Internet. Mostly, virtual networks appear like a single LAN, even though +they can span the entire world. But virtual networks can't be secured +by using firewalls, because the traffic that flows through it has to go +through the Internet, where other people can look at it. + +As is the case with either type of VPN, anybody could eavesdrop. Or +worse, alter data. Hence it's probably advisable to encrypt the data that flows over the network. +When one introduces encryption, we can form a true VPN. Other people may +see encrypted traffic, but if they don't know how to decipher it (they +need to know the key for that), they cannot read the information that flows +through the VPN. This is what tinc was made for. + @c ================================================================== -@node tinc, , VPNs, Introduction +@node tinc @section tinc +@cindex vpnd I really don't quite remember what got us started, but it must have been -Guus' idea. He wrote a simple implementation (about 50 lines of C) that -used the @emph{ethertap} device that Linux knows of since somewhere -about kernel 2.1.60. It didn't work immediately and he improved it a -bit. At this stage, the project was still simply called @samp{vpnd}. +Guus' idea. He wrote a simple implementation (about 50 lines of C) that +used the ethertap device that Linux knows of since somewhere +about kernel 2.1.60. It didn't work immediately and he improved it a +bit. At this stage, the project was still simply called "vpnd". Since then, a lot has changed---to say the least. @cindex tincd -tinc now supports encryption, it consists of a single daemon (tincd) for +Tinc now supports encryption, it consists of a single daemon (tincd) for both the receiving and sending end, it has become largely runtime-configurable---in short, it has become a full-fledged professional package. -A lot can---and will be---changed. I have a few things that I'd like to -see in the future releases of tinc. Not everything will be available in -the near future. Our first objective is to make tinc work perfectly as +@cindex traditional VPNs +@cindex scalability +Tinc also allows more than two sites to connect to eachother and form a single VPN. +Traditionally VPNs are created by making tunnels, which only have two endpoints. +Larger VPNs with more sites are created by adding more tunnels. +Tinc takes another approach: only endpoints are specified, +the software itself will take care of creating the tunnels. +This allows for easier configuration and improved scalability. + +A lot can---and will be---changed. We have a number of things that we would like to +see in the future releases of tinc. Not everything will be available in +the near future. Our first objective is to make tinc work perfectly as it stands, and then add more advanced features. -Meanwhile, we're always open-minded towards new ideas. And we're +Meanwhile, we're always open-minded towards new ideas. And we're available too. @c ================================================================== -@node Configuring a Linux system, Installing tinc, Introduction, Top -@chapter Configuring a Linux system +@node Supported platforms +@section Supported platforms + +@cindex platforms +Tinc has been verified to work under Linux, FreeBSD, OpenBSD, NetBSD, MacOS/X (Darwin), Solaris, and Windows (both natively and in a Cygwin environment), +with various hardware architectures. These are some of the platforms +that are supported by the universal tun/tap device driver or other virtual network device drivers. +Without such a driver, tinc will most +likely compile and run, but it will not be able to send or receive data +packets. + +@cindex release +For an up to date list of supported platforms, please check the list on +our website: +@uref{https://www.tinc-vpn.org/platforms/}. + +@c +@c +@c +@c +@c +@c +@c Preparing your system +@c +@c +@c +@c +@c -This chapter contains information on how a Linux system is configured -for the use of tinc. +@c ================================================================== +@node Preparations +@chapter Preparations + +This chapter contains information on how to prepare your system to +support tinc. @menu -* Configuring the kernel:: -* Files Needed:: -* Setting up the devices:: +* Configuring the kernel:: +* Libraries:: @end menu @c ================================================================== -@node Configuring the kernel, Files Needed, Configuring a Linux system, Configuring a Linux system +@node Configuring the kernel @section Configuring the kernel -Since this particular implementation only runs on 2.1 or higher Linux -kernels, you should grab one (2.2 is current at this time). A 2.0 port -is not really possible, unless someone tells me someone ported the -ethertap and netlink devices back to 2.0. +@menu +* Configuration of Linux kernels:: +* Configuration of FreeBSD kernels:: +* Configuration of OpenBSD kernels:: +* Configuration of NetBSD kernels:: +* Configuration of Solaris kernels:: +* Configuration of Darwin (MacOS/X) kernels:: +* Configuration of Windows:: +@end menu + -If you are unfamiliar with the process of configuring and compiling a -new kernel, you should read the -@uref{http://howto.linuxberg.com/LDP/HOWTO/Kernel-HOWTO.html, Kernel -HOWTO} first. Do that now! +@c ================================================================== +@node Configuration of Linux kernels +@subsection Configuration of Linux kernels -Here are the options you have to turn on/off when configuring a new -kernel. +@cindex Universal tun/tap +For tinc to work, you need a kernel that supports the Universal tun/tap device. +Most distributions come with kernels that already support this. +Here are the options you have to turn on when configuring a new kernel: @example Code maturity level options [*] Prompt for development and/or incomplete code/drivers -Networking options -[*] Kernel/User netlink socket -<*> Netlink device emulation Network device support -<*> Ethertap network tap + Universal tun/tap device driver support @end example -Any other options not mentioned here are not relevant to tinc. If you -decide to build any of these as dynamic kernel modules, it's a good idea -to add these lines to @file{/etc/modules.conf}. +It's not necessary to compile this driver as a module, even if you are going to +run more than one instance of tinc. + +If you decide to build the tun/tap driver as a kernel module, add these lines +to @file{/etc/modules.conf}: @example -alias tap0 ethertap -alias char-major-36 netlink_dev +alias char-major-10-200 tun @end example -Finally, after having set up other options, build the kernel and boot -it. Unfortunately it's not possible to insert these modules in a running -kernel. - @c ================================================================== -@node Files Needed, Setting up the devices, Configuring the kernel, Configuring a Linux system -@section Files Needed +@node Configuration of FreeBSD kernels +@subsection Configuration of FreeBSD kernels -@subsubheading Device files +For FreeBSD version 4.1 and higher, tun and tap drivers are included in the default kernel configuration. +The tap driver can be loaded with @code{kldload if_tap}, or by adding @code{if_tap_load="YES"} to @file{/boot/loader.conf}. -First, you'll need the special device file(s) that form the interface -between the kernel and the daemon. -@example -mknod -m 600 /dev/tap0 c 36 16 -chown 0.0 /dev/tap0 -@end example +@c ================================================================== +@node Configuration of OpenBSD kernels +@subsection Configuration of OpenBSD kernels -The permissions now will be such that only the super user may read/write -to this file. You'd want this, because otherwise eavesdropping would -become a bit too easy. This does, however, imply that you'd have to run -tincd as root. +Recent versions of OpenBSD come with both tun and tap devices enabled in the default kernel configuration. -If you want to, you may also create more device files, which would be -numbered 0...15, with minor device numbers 16...31. They all should be -owned by root and have permission 600. +@c ================================================================== +@node Configuration of NetBSD kernels +@subsection Configuration of NetBSD kernels -@subsubheading @file{/etc/networks} +For NetBSD version 1.5.2 and higher, +the tun driver is included in the default kernel configuration. -You may add a line to @file{/etc/networks} so that your VPN will get a -symbolic name. For example: +Tunneling IPv6 may not work on NetBSD's tun device. -@example -myvpn 10.0.0.0 -@end example +@c ================================================================== +@node Configuration of Solaris kernels +@subsection Configuration of Solaris kernels -@subsubheading @file{/etc/services} +For Solaris 8 (SunOS 5.8) and higher, +the tun driver may or may not be included in the default kernel configuration. +If it isn't, the source can be downloaded from @uref{http://vtun.sourceforge.net/tun/}. +For x86 and sparc64 architectures, precompiled versions can be found at @uref{https://www.monkey.org/~dugsong/fragroute/}. +If the @file{net/if_tun.h} header file is missing, install it from the source package. -You may add this line to @file{/etc/services}. The effect is that you -may supply a @samp{tinc} as a valid port number to some programs. The -number 655 is registered with the IANA. -@example -tinc 655/tcp TINC -tinc 655/udp TINC -# Ivo Timmermans -@end example +@c ================================================================== +@node Configuration of Darwin (MacOS/X) kernels +@subsection Configuration of Darwin (MacOS/X) kernels + +Tinc on Darwin relies on a tunnel driver for its data acquisition from the kernel. +OS X version 10.6.8 and later have a built-in tun driver called "utun". +Tinc also supports the driver from @uref{http://tuntaposx.sourceforge.net/}, +which supports both tun and tap style devices, + +By default, tinc expects the tuntaposx driver to be installed. +To use the utun driver, set add @code{Device = utunX} to @file{tinc.conf}, +where X is the desired number for the utun interface. +You can also omit the number, in which case the first free number will be chosen. @c ================================================================== -@node Setting up the devices, , Files Needed, Configuring a Linux system -@section Setting up the devices +@node Configuration of Windows +@subsection Configuration of Windows -Before you can start transmitting data over the tinc tunnel, you must -set up the ethertap network devices. +You will need to install the latest TAP-Win32 driver from OpenVPN. +You can download it from @uref{https://openvpn.net/index.php/open-source/downloads.html}. +Using the Network Connections control panel, +configure the TAP-Win32 network interface in the same way as you would do from the tinc-up script, +as explained in the rest of the documentation. -First, decide which IP addresses you want to have associated with these -devices, and what network mask they must have. You also need these -numbers when you are going to configure tinc itself. @xref{Configuring -tinc}. -It doesn't matter much which part you do first, setting up the network -devices or configure tinc. But they both have to be done before you try -to start a tincd. +@c ================================================================== +@node Libraries +@section Libraries -The actual setup of the ethertap device is quite simple, just repeat -after me: +@cindex requirements +@cindex libraries +Before you can configure or build tinc, you need to have the LibreSSL or OpenSSL, zlib, +lzo, curses and readline libraries installed on your system. If you try to +configure tinc without having them installed, configure will give you an error +message, and stop. + +@menu +* LibreSSL/OpenSSL:: +* zlib:: +* lzo:: +* libcurses:: +* libreadline:: +@end menu -@example -ifconfig tap@emph{n} hw ether fe:fd:@emph{xx}:@emph{xx}:@emph{xx}:@emph{xx} -@end example -The @emph{n} here is the number of the ethertap device you want to -use. It should be the same @emph{n} as the one you use for -@file{/dev/tap@emph{n}}. The @emph{xx}s are four hexadecimal numbers -(0--ff). With previous versions of tincd, it didn't matter what they -were. But newer kernels require properly set up ethernet addresses. -In fact, the old behavior was wrong. It is required that the @emph{xx}s -match MyOwnVPNIP. +@c ================================================================== +@node LibreSSL/OpenSSL +@subsection LibreSSL/OpenSSL + +@cindex LibreSSL +@cindex OpenSSL +For all cryptography-related functions, tinc uses the functions provided +by the LibreSSL or the OpenSSL library. + +If this library is not installed, you wil get an error when configuring +tinc for build. Support for running tinc with other cryptographic libraries +installed @emph{may} be added in the future. + +You can use your operating system's package manager to install this if +available. Make sure you install the development AND runtime versions +of this package. + +If your operating system comes neither with LibreSSL or OpenSSL, you have to +install one manually. It is recommended that you get the latest version of +LibreSSL from @url{http://www.libressl.org/}. Instructions on how to +configure, build and install this package are included within the package. +Please make sure you build development and runtime libraries (which is the +default). + +If you installed the LibreSSL or OpenSSL libraries from source, it may be necessary +to let configure know where they are, by passing configure one of the +--with-openssl-* parameters. Note that you even have to use --with-openssl-* if you +are using LibreSSL. @example -ifconfig tap@emph{n} @emph{IP} netmask @emph{mask} +--with-openssl=DIR LibreSSL/OpenSSL library and headers prefix +--with-openssl-include=DIR LibreSSL/OpenSSL headers directory + (Default is OPENSSL_DIR/include) +--with-openssl-lib=DIR LibreSSL/OpenSSL library directory + (Default is OPENSSL_DIR/lib) @end example -This will activate the device with an IP address @emph{IP} with network -mask @emph{mask}. +@subsubheading License +@cindex license +The complete source code of tinc is covered by the GNU GPL version 2. +Since the license under which OpenSSL is distributed is not directly +compatible with the terms of the GNU GPL +@uref{https://www.openssl.org/support/faq.html#LEGAL2}, we +include an exemption to the GPL (see also the file COPYING.README) to allow +everyone to create a statically or dynamically linked executable: -@c ================================================================== -@node Installing tinc, Configuring tinc, Configuring a Linux system, Top -@chapter Installing tinc +@quotation +This program is released under the GPL with the additional exemption +that compiling, linking, and/or using OpenSSL is allowed. You may +provide binary packages linked to the OpenSSL libraries, provided that +all other requirements of the GPL are met. +@end quotation -First download it. This is the -@uref{http://tinc.nl.linux.org/download.html, download -page}, which has the checksums of these files listed; you may wish to -check these with md5sum before continuing. +Since the LZO library used by tinc is also covered by the GPL, +we also present the following exemption: -tinc comes in a handy autoconf/automake package, which you can just -treat the same as any other package. Which is just untar it, type -`configure' and then `make'. +@quotation +Hereby I grant a special exception to the tinc VPN project +(https://www.tinc-vpn.org/) to link the LZO library with the OpenSSL library +(https://www.openssl.org). -More detailed instructions are in the file @file{INSTALL}, which is -included in the source distribution. +Markus F.X.J. Oberhumer +@end quotation @c ================================================================== -@node Configuring tinc, Running tinc, Installing tinc, Top -@chapter Configuring tinc +@node zlib +@subsection zlib -@menu -* Multiple networks:: -* How connections work:: -* Configuration file:: -* Example:: -@end menu +@cindex zlib +For the optional compression of UDP packets, tinc uses the functions provided +by the zlib library. +If this library is not installed, you wil get an error when running the +configure script. You can either install the zlib library, or disable support +for zlib compression by using the "--disable-zlib" option when running the +configure script. Note that if you disable support for zlib, the resulting +binary will not work correctly on VPNs where zlib compression is used. -@c ================================================================== -@node Multiple networks, How connections work, Configuring tinc, Configuring tinc -@section Multiple networks +You can use your operating system's package manager to install this if +available. Make sure you install the development AND runtime versions +of this package. + +If you have to install zlib manually, you can get the source code +from @url{http://www.zlib.net/}. Instructions on how to configure, +build and install this package are included within the package. Please +make sure you build development and runtime libraries (which is the +default). -@c from the manpage -It is perfectly OK for you to run more than one tinc daemon. -However, in its default form, you will soon notice that you can't use -two different configuration files without the -c option. +@c ================================================================== +@node lzo +@subsection lzo -We have thought of another way of dealing with this: network names. This -means that you call tincd with the -n argument, which will assign a name -to this daemon. +@cindex lzo +Another form of compression is offered using the LZO library. -The effect of this is that the daemon will set its configuration -``root'' to /etc/tinc/nn/, where nn is your argument to the -n -option. You'll notice that it appears in syslog as ``tincd.nn''. +If this library is not installed, you wil get an error when running the +configure script. You can either install the LZO library, or disable support +for LZO compression by using the "--disable-lzo" option when running the +configure script. Note that if you disable support for LZO, the resulting +binary will not work correctly on VPNs where LZO compression is used. -However, it is not strictly necessary that you call tinc with the -n -option. In this case, the network name would just be empty, and it will -be used as such. tinc now looks for files in /etc/tinc/, instead of -/etc/tinc/nn/; the configuration file should be /etc/tinc/tincd.conf, -and the passphrases are now expected to be in /etc/tinc/passphrases/. +You can use your operating system's package manager to install this if +available. Make sure you install the development AND runtime versions +of this package. -But it is highly recommended that you use this feature of tinc, because -it will be so much clearer whom your daemon talks to. Hence, we will -assume that you use it. +If you have to install lzo manually, you can get the source code +from @url{https://www.oberhumer.com/opensource/lzo/}. Instructions on how to configure, +build and install this package are included within the package. Please +make sure you build development and runtime libraries (which is the +default). @c ================================================================== -@node How connections work, Configuration file, Multiple networks, Configuring tinc -@section How connections work +@node libcurses +@subsection libcurses + +@cindex libcurses +For the "tinc top" command, tinc requires a curses library. -Before going on, first a bit on how tinc sees connections. +If this library is not installed, you wil get an error when running the +configure script. You can either install a suitable curses library, or disable +all functionality that depends on a curses library by using the +"--disable-curses" option when running the configure script. -When tinc starts up, it reads in the configuration file and parses the -command-line options. If it sees a `ConnectTo' value in the file, it -will try to connect to it, on the given port. If this fails, tinc exits. +There are several curses libraries. It is recommended that you install +"ncurses" (@url{http://invisible-island.net/ncurses/}), +however other curses libraries should also work. +In particular, "PDCurses" (@url{http://pdcurses.sourceforge.net/}) +is recommended if you want to compile tinc for Windows. + +You can use your operating system's package manager to install this if +available. Make sure you install the development AND runtime versions +of this package. @c ================================================================== -@node Configuration file, Example, How connections work, Configuring tinc -@section Configuration file +@node libreadline +@subsection libreadline -The actual configuration of the daemon is done in the file -@file{/etc/tinc/nn/tincd.conf}. +@cindex libreadline +For the "tinc" command's shell functionality, tinc uses the readline library. -This file consists of comments (lines started with a #) or assignments -in the form of +If this library is not installed, you wil get an error when running the +configure script. You can either install a suitable readline library, or +disable all functionality that depends on a readline library by using the +"--disable-readline" option when running the configure script. -@example -Variable = Value. -@end example +You can use your operating system's package manager to install this if +available. Make sure you install the development AND runtime versions +of this package. -The variable names are case insensitive, and any spaces, tabs, newlines -and carriage returns are ignored. Note: it is not required that you put -in the `=' sign, but doing so improves readability. If you leave it -out, remember to replace it with at least one space character. +If you have to install libreadline manually, you can get the source code from +@url{http://www.gnu.org/software/readline/}. Instructions on how to configure, +build and install this package are included within the package. Please make +sure you build development and runtime libraries (which is the default). -@menu -* Variables:: -@end menu + +@c +@c +@c +@c Installing tinc +@c +@c +@c +@c @c ================================================================== -@node Variables, , Configuration file, Configuration file -@subsection Variables +@node Installation +@chapter Installation -Here are all valid variables, listed in alphabetical order: +If you use Debian, you may want to install one of the +precompiled packages for your system. These packages are equipped with +system startup scripts and sample configurations. -@c straight from the manpage -@table @asis -@item AllowConnect = (yes|no) -If set to yes, anyone may try to connect to you. If you set this to no, -no incoming connections will be accepted. This does not affect the -outgoing connections. - -@item ConnectPort = port -Connect to the upstream host (given with the ConnectTo directive) on -port port. port may be given in decimal (default), octal (when preceded -by a single zero) or hexadecimal (prefixed with 0x). port is the port -number for both the UDP and the TCP (meta) connections. - -@item ConnectTo = (IP address|hostname) -Specifies which host to connect to on startup. If the ConnectPort -variable is omitted, then tinc will try to connect to port 655. - -If you don't specify a host with ConnectTo, regardless of whether a -value for ConnectPort is given, tinc won't connect at all, and will -instead just listen for incoming connections. Only the initiator of a -tinc VPN should need this. - -@item ListenPort = port -Listen on local port port. The computer connecting to this daemon should -use this number as the argument for his ConnectPort. Again, the -default is 655. - -@item MyOwnVPNIP = local address[/maskbits] -The local address is the number that the daemon will propagate to -other daemons on the network when it is identifying itself. Hence this -will be the file name of the passphrase file that the other end expects -to find the passphrase in. - -The local address is the IP address of the tap device, not the real IP -address of the host running tincd. Due to changes in recent kernels, it -is also necessary that you make the ethernet (also known as MAC) address -equal to the IP address (see the example). - -maskbits is the number of bits set to 1 in the netmask part. - -@item MyVirtualIP = local address[/maskbits] -This is an alias for MyOwnVPNIP. - -@item Passphrases = directory -The directory where tinc will look for passphrases when someone tries to -connect. Please see the manpage for genauth(8) for more information -about passphrases as used by tinc. - -@item PingTimeout = number -The number of seconds of inactivity that tinc will wait before sending a -probe to the other end. If that other end doesn't answer within that -same amount of seconds, the connection is terminated, and the others -will be notified of this. +If you cannot use one of the precompiled packages, or you want to compile tinc +for yourself, you can use the source. The source is distributed under +the GNU General Public License (GPL). Download the source from the +@uref{https://www.tinc-vpn.org/download/, download page}. -@item TapDevice = device -The ethertap device to use. Note that you can only use one device per -daemon. The info pages of the tinc package contain more information -about configuring an ethertap device for Linux. +Tinc comes in a convenient autoconf/automake package, which you can just +treat the same as any other package. Which is just untar it, type +`./configure' and then `make'. +More detailed instructions are in the file @file{INSTALL}, which is +included in the source distribution. -@end table +@menu +* Building and installing tinc:: +* System files:: +@end menu @c ================================================================== -@node Example, , Configuration file, Configuring tinc -@section Example - -Imagine the following situation. An A-based company wants to connect -three branch offices in B, C and D using the internet. All four offices -have a 24/7 connection to the internet. +@node Building and installing tinc +@section Building and installing tinc -A is going to serve as the center of the network. B and C will connect -to A, and D will connect to C. Each office will be assigned their own IP -network, 10.x.0.0. +Detailed instructions on configuring the source, building tinc and installing tinc +can be found in the file called @file{INSTALL}. -@example -A: net 10.1.0.0 mask 255.255.0.0 gateway 10.1.54.1 internet IP 1.2.3.4 -B: net 10.2.0.0 mask 255.255.0.0 gateway 10.2.1.12 internet IP 2.3.4.5 -C: net 10.3.0.0 mask 255.255.0.0 gateway 10.3.69.254 internet IP 3.4.5.6 -D: net 10.4.0.0 mask 255.255.0.0 gateway 10.4.3.32 internet IP 4.5.6.7 -@end example +@cindex binary package +If you happen to have a binary package for tinc for your distribution, +you can use the package management tools of that distribution to install tinc. +The documentation that comes along with your distribution will tell you how to do that. -``gateway'' is the VPN IP address of the machine that is running the -tincd. ``internet IP'' is the IP address of the firewall, which does not -need to run tincd, but it must do a port forwarding of TCP&UDP on port -655 (unless otherwise configured). +@menu +* Darwin (MacOS/X) build environment:: +* Cygwin (Windows) build environment:: +* MinGW (Windows) build environment:: +@end menu -In this example, it is assumed that eth0 is the interface that points to -the inner LAN of the office. This could be the same as the interface -that leads to the internet. -@subsubheading For A +@c ================================================================== +@node Darwin (MacOS/X) build environment +@subsection Darwin (MacOS/X) build environment -@emph{A} would be configured like this: +In order to build tinc on Darwin, you need to install Xcode from @uref{https://developer.apple.com/xcode/}. +It might also help to install a recent version of Fink from @uref{http://www.finkproject.org/}. -@example -ifconfig tap0 hw ether fe:fd:0a:01:36:01 -ifconfig tap0 10.1.54.1 netmask 255.0.0.0 -ifconfig eth0 10.1.54.1 netmask 255.255.0.0 broadcast 10.1.255.255 -@end example +You need to download and install LibreSSL (or OpenSSL) and LZO, +either directly from their websites (see @ref{Libraries}) or using Fink. -and in /etc/tinc/tincd.conf: +@c ================================================================== +@node Cygwin (Windows) build environment +@subsection Cygwin (Windows) build environment -@example -TapDevice = /dev/tap0 -MyVirtualIP = 10.1.54.1/16 -@end example +If Cygwin hasn't already been installed, install it directly from +@uref{https://www.cygwin.com/}. -@subsubheading For B +When tinc is compiled in a Cygwin environment, it can only be run in this environment, +but all programs, including those started outside the Cygwin environment, will be able to use the VPN. +It will also support all features. -@example -ifconfig tap0 hw ether fe:fd:0a:02:01:0c -ifconfig tap0 10.2.1.12 netmask 255.0.0.0 -ifconfig eth0 10.2.43.8 netmask 255.255.0.0 broadcast 10.2.255.255 -@end example +@c ================================================================== +@node MinGW (Windows) build environment +@subsection MinGW (Windows) build environment -and in /etc/tinc/tincd.conf: +You will need to install the MinGW environment from @uref{http://www.mingw.org}. +You also need to download and install LibreSSL (or OpenSSL) and LZO. -@example -TapDevice = /dev/tap0 -MyVirtualIP = 10.2.1.12/16 -ConnectTo = 1.2.3.4 -AllowConnect = no -@end example +When tinc is compiled using MinGW it runs natively under Windows, +it is not necessary to keep MinGW installed. -Note here that the internal address (on eth0) doesn't have to be the -same as on the tap0 device. Also, ConnectTo is given so that no-one can -connect to this node. +When detaching, tinc will install itself as a service, +which will be restarted automatically after reboots. -@subsubheading For C -@example -ifconfig tap0 hw ether fe:fd:0a:03:45:fe -ifconfig tap0 10.3.69.254 netmask 255.0.0.0 -ifconfig eth0 10.3.69.254 netmask 255.255.0.0 broadcast 10.3.255.255 -@end example +@c ================================================================== +@node System files +@section System files -and in /etc/tinc/A/tincd.conf: +Before you can run tinc, you must make sure you have all the needed +files on your system. -@example -MyVirtualIP = 10.3.69.254/16 -ConnectTo = 1.2.3.4 -ListenPort = 2000 -@end example +@menu +* Device files:: +* Other files:: +@end menu -C already has another daemon that runs on port 655, so they have to -reserve another port for tinc. They also use the netname to distinguish -between the two. tinc is started with `tincd -n A'. -@subsubheading For D +@c ================================================================== +@node Device files +@subsection Device files -@example -ifconfig tap0 hw ether fe:fd:0a:04:03:20 -ifconfig tap0 10.4.3.32 netmask 255.0.0.0 -ifconfig tap0 10.4.3.32 netmask 255.255.0.0 broadcast 10.4.255.255 -@end example +@cindex device files +Most operating systems nowadays come with the necessary device files by default, +or they have a mechanism to create them on demand. -and in /etc/tinc/tincd.conf: +If you use Linux and do not have udev installed, +you may need to create the following device file if it does not exist: @example -MyVirtualIP = 10.4.3.32/16 -ConnectTo = 3.4.5.6 -ConnectPort = 2000 -AllowConnect = no +mknod -m 600 /dev/net/tun c 10 200 @end example -D will be connecting to C, which has a tincd running for this network on -port 2000. Hence they need to put in a ConnectPort. - -@subsubheading Authentication -A, B, C and D all generate a passphrase with genauth 2048, the output is -stored in /etc/tinc/passphrases/local, except for C, where it should be -/etc/tinc/A/passphrases/local. - -A stores a copy of B's passphrase in /etc/tinc/passphrases/10.2.0.0 +@c ================================================================== +@node Other files +@subsection Other files -A stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.0.0 +@subsubheading @file{/etc/networks} -B stores a copy of A's passphrase in /etc/tinc/passphrases/10.1.0.0 +You may add a line to @file{/etc/networks} so that your VPN will get a +symbolic name. For example: -C stores a copy of A's passphrase in /etc/tinc/A/passphrases/10.1.0.0 +@example +myvpn 10.0.0.0 +@end example -C stores a copy of D's passphrase in /etc/tinc/A/passphrases/10.4.0.0 +@subsubheading @file{/etc/services} -D stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.0.0 +@cindex port numbers +You may add this line to @file{/etc/services}. The effect is that you +may supply a @samp{tinc} as a valid port number to some programs. The +number 655 is registered with the IANA. -@subsubheading Starting +@example +tinc 655/tcp TINC +tinc 655/udp TINC +# Ivo Timmermans +@end example -A has to start their tincd first. Then come B and C, where C has to -provide the option `-n A', because they have more than one tinc -network. Finally, D's tincd is started. +@c +@c +@c +@c +@c Configuring tinc +@c +@c +@c +@c @c ================================================================== -@node Running tinc, Technical information, Configuring tinc, Top -@chapter Running tinc - -Running tinc isn't just as easy as typing `tincd' and hoping everything -will just work out the way you wanted. Instead, the use of tinc is a -project that involves trust relations and more than one computer. +@node Configuration +@chapter Configuration @menu -* Managing keys:: -* Runtime options:: +* Configuration introduction:: +* Multiple networks:: +* How connections work:: +* Configuration files:: +* Network interfaces:: +* Example configuration:: @end menu - @c ================================================================== -@node Managing keys, Runtime options, Running tinc, Running tinc -@section Managing keys +@node Configuration introduction +@section Configuration introduction + +Before actually starting to configure tinc and editing files, +make sure you have read this entire section so you know what to expect. +Then, make it clear to yourself how you want to organize your VPN: +What are the nodes (computers running tinc)? +What IP addresses/subnets do they have? +What is the network mask of the entire VPN? +Do you need special firewall rules? +Do you have to set up masquerading or forwarding rules? +Do you want to run tinc in router mode or switch mode? +These questions can only be answered by yourself, +you will not find the answers in this documentation. +Make sure you have an adequate understanding of networks in general. +@cindex Network Administrators Guide +A good resource on networking is the +@uref{http://www.tldp.org/LDP/nag2/, Linux Network Administrators Guide}. + +If you have everything clearly pictured in your mind, +proceed in the following order: +First, create the initial configuration files and public/private keypairs using the following command: +@example +tinc -n @var{NETNAME} init @var{NAME} +@end example +Second, use @samp{tinc -n @var{NETNAME} add ...} to further configure tinc. +Finally, export your host configuration file using @samp{tinc -n @var{NETNAME} export} and send it to those +people or computers you want tinc to connect to. +They should send you their host configuration file back, which you can import using @samp{tinc -n @var{NETNAME} import}. -Before attempting to start tinc, you have to create passphrases. When -tinc tries to make a connection, it exchanges some sensitive -data. Before doing so, it likes to know if the other end is -trustworthy. +These steps are described in the subsections below. -To do this, both ends must have some knowledge about the other. In the -case of tinc this is the authentication passphrase. -This passphrase is a number, which is chosen at random. This number is -then sent to the other computers which want to talk to us directly. To -avoid breaking security, this should be done over a known secure channel -(such as ssh or similar). +@c ================================================================== +@node Multiple networks +@section Multiple networks -All passphrases are stored in the passphrases directory, which is -normally /etc/tinc/nn/passphrases/, but it may be changed using the -`Passphrases' option in the config file. +@cindex multiple networks +@cindex netname -To generate a passphrase, run `genauth'. genauth takes one argument, -which is the length of the passphrase in bits. The length of the -passphrase should be in the range 1024--2048 for a key length of 128 -bits. genauth creates a random number of the specified length, and puts -it to stdout. +In order to allow you to run more than one tinc daemon on one computer, +for instance if your computer is part of more than one VPN, +you can assign a @var{netname} to your VPN. +It is not required if you only run one tinc daemon, +it doesn't even have to be the same on all the nodes of your VPN, +but it is recommended that you choose one anyway. -Every computer that wants to participate in the VPN should do this, and -store the output in the passphrases directory, in the file @file{local}. +We will asume you use a netname throughout this document. +This means that you call tinc with the -n argument, +which will specify the netname. -When every computer has his own local key, it should copy it to the -computer that it wants to talk to directly. (i.e. the one it connects to -during startup.) This should be done via a secure channel, because it is -sensitive information. If this is not done securely, someone might break -in on you later on. +The effect of this option is that tinc will set its configuration +root to @file{@value{sysconfdir}/tinc/@var{netname}/}, where @var{netname} is your argument to the -n option. +You will also notice that log messages it appears in syslog as coming from @file{tinc.@var{netname}}, +and on Linux, unless specified otherwise, the name of the virtual network interface will be the same as the network name. -Those non-local passphrase files must have the name of the VPN IP -address that they will advertise to you. For instance, if a computer -tells us it likes to be 10.1.1.3 with netmask 255.255.0.0, the file -should still be called 10.1.1.3, and not 10.1.0.0. +However, it is not strictly necessary that you call tinc with the -n +option. If you do not use it, the network name will just be empty, and +tinc will look for files in @file{@value{sysconfdir}/tinc/} instead of +@file{@value{sysconfdir}/tinc/@var{netname}/}; +the configuration file will then be @file{@value{sysconfdir}/tinc/tinc.conf}, +and the host configuration files are expected to be in @file{@value{sysconfdir}/tinc/hosts/}. @c ================================================================== -@node Runtime options, , Managing keys, Running tinc -@section Runtime options +@node How connections work +@section How connections work -Besides the settings in the configuration file, tinc also accepts some -command line options. +When tinc starts up, it parses the command-line options and then +reads in the configuration file tinc.conf. +If it sees one or more `ConnectTo' values pointing to other tinc daemons in that file, +it will try to connect to those other daemons. +Whether this succeeds or not and whether `ConnectTo' is specified or not, +tinc will listen for incoming connection from other deamons. +If you did specify a `ConnectTo' value and the other side is not responding, +tinc will keep retrying. +This means that once started, tinc will stay running until you tell it to stop, +and failures to connect to other tinc daemons will not stop your tinc daemon +for trying again later. +This means you don't have to intervene if there are temporary network problems. + +@cindex client +@cindex server +There is no real distinction between a server and a client in tinc. +If you wish, you can view a tinc daemon without a `ConnectTo' value as a server, +and one which does specify such a value as a client. +It does not matter if two tinc daemons have a `ConnectTo' value pointing to each other however. + +Connections specified using `ConnectTo' are so-called meta-connections. +Tinc daemons exchange information about all other daemon they know about via these meta-connections. +After learning about all the daemons in the VPN, +tinc will create other connections as necessary in order to communicate with them. +For example, if there are three daemons named A, B and C, and A has @samp{ConnectTo = B} in its tinc.conf file, +and C has @samp{ConnectTo = B} in its tinc.conf file, then A will learn about C from B, +and will be able to exchange VPN packets with C without the need to have @samp{ConnectTo = C} in its tinc.conf file. + +It could be that some daemons are located behind a Network Address Translation (NAT) device, or behind a firewall. +In the above scenario with three daemons, if A and C are behind a NAT, +B will automatically help A and C punch holes through their NAT, +in a way similar to the STUN protocol, so that A and C can still communicate with each other directly. +It is not always possible to do this however, and firewalls might also prevent direct communication. +In that case, VPN packets between A and C will be forwarded by B. + +In effect, all nodes in the VPN will be able to talk to each other, as long as +their is a path of meta-connections between them, and whenever possible, two +nodes will communicate with each other directly. -This list is a longer version of that in the manpage. The latter is -generated automatically, so may be more up-to-date. -@c from the manpage -@table @asis -@item -c, --config=FILE -Read configuration options from FILE. The default is -@file{/etc/tinc/nn/tincd.conf}. +@c ================================================================== +@node Configuration files +@section Configuration files -@item -d -Increase debug level. The higher it gets, the more gets -logged. Everything goes via syslog. +The actual configuration of the daemon is done in the file +@file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf} and at least one other file in the directory +@file{@value{sysconfdir}/tinc/@var{netname}/hosts/}. -0 is the default, only some basic information connection attempts get -logged. Setting it to 1 will log a bit more, still not very -disturbing. With two -d's tincd will log protocol information, which can -get pretty noisy. Three or more -d's will output every single packet -that goes out or comes in, which probably generates more data than the -packets themselves. +An optionnal directory @file{@value{sysconfdir}/tinc/@var{netname}/conf.d} can be added from which +any .conf file will be read. -@item -k, --kill -Attempt to kill a running tincd and exit. A TERM signal (15) gets sent -to the daemon that his its PID in /var/run/tincd.nn.pid. +These file consists of comments (lines started with a #) or assignments +in the form of -Because it kills only one tincd, you should use -n here if you use it -normally. +@example +Variable = Value. +@end example -@item -n, --net=NETNAME -Connect to net NETNAME. @xref{Multiple networks}. +The variable names are case insensitive, and any spaces, tabs, newlines +and carriage returns are ignored. Note: it is not required that you put +in the `=' sign, but doing so improves readability. If you leave it +out, remember to replace it with at least one space character. -@item -t, --timeout=TIMEOUT -Seconds to wait before giving a timeout. Should not be set too low, -because every time tincd senses a timeout, it disconnects and reconnects -again, which will cause unnecessary network traffic and log messages. +The server configuration is complemented with host specific configuration (see +the next section). Although all host configuration options for the local node +listed in this document can also be put in +@file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf}, it is recommended to +put host specific configuration options in the host configuration file, as this +makes it easy to exchange with other nodes. -@item --help -Display a short reminder of these runtime options and terminate. +You can edit the config file manually, but it is recommended that you use +the tinc command to change configuration variables for you. -@item --version -Output version information and exit. +In the following two subsections all valid variables are listed in alphabetical order. +The default value is given between parentheses, +other comments are between square brackets. -@end table +@menu +* Main configuration variables:: +* Host configuration variables:: +* Scripts:: +* How to configure:: +@end menu @c ================================================================== -@node Technical information, About us, Running tinc, Top -@chapter Technical information +@node Main configuration variables +@subsection Main configuration variables +@table @asis +@cindex AddressFamily +@item AddressFamily = (any) +This option affects the address family of listening and outgoing sockets. +If any is selected, then depending on the operating system +both IPv4 and IPv6 or just IPv6 listening sockets will be created. + +@cindex AutoConnect +@item AutoConnect = (no) [experimental] +If set to yes, tinc will automatically set up meta connections to other nodes, +without requiring @var{ConnectTo} variables. + +@cindex BindToAddress +@item BindToAddress = <@var{address}> [<@var{port}>] +This is the same as ListenAddress, however the address given with the BindToAddress option +will also be used for outgoing connections. +This is useful if your computer has more than one IPv4 or IPv6 address, +and you want tinc to only use a specific one for outgoing packets. + +@cindex BindToInterface +@item BindToInterface = <@var{interface}> [experimental] +If you have more than one network interface in your computer, tinc will +by default listen on all of them for incoming connections. It is +possible to bind tinc to a single interface like eth0 or ppp0 with this +variable. + +This option may not work on all platforms. +Also, on some platforms it will not actually bind to an interface, +but rather to the address that the interface has at the moment a socket is created. + +@cindex Broadcast +@item Broadcast = (mst) [experimental] +This option selects the way broadcast packets are sent to other daemons. +@emph{NOTE: all nodes in a VPN must use the same Broadcast mode, otherwise routing loops can form.} -@c ================================================================== -@menu -* The Connection:: -* Security:: -* The Protocol:: -@end menu +@table @asis +@item no +Broadcast packets are never sent to other nodes. -@node The Connection, Security, Technical information, Technical information -@section The basic philosophy of the way tinc works -@cindex Connection +@item mst +Broadcast packets are sent and forwarded via the VPN's Minimum Spanning Tree. +This ensures broadcast packets reach all nodes. -tinc is a daemon that takes VPN data and transmit that to another host -computer over the existing Internet infrastructure. +@item direct +Broadcast packets are sent directly to all nodes that can be reached directly. +Broadcast packets received from other nodes are never forwarded. +If the IndirectData option is also set, broadcast packets will only be sent to nodes which we have a meta connection to. +@end table -@menu -* Protocol Preview:: -* The Meta-connection:: -@end menu +@cindex BroadcastSubnet +@item BroadcastSubnet = @var{address}[/@var{prefixlength}] +Declares a broadcast subnet. +Any packet with a destination address falling into such a subnet will be routed as a broadcast +(provided all nodes have it declared). +This is most useful to declare subnet broadcast addresses (e.g. 10.42.255.255), +otherwise tinc won't know what to do with them. + +Note that global broadcast addresses (MAC ff:ff:ff:ff:ff:ff, IPv4 255.255.255.255), +as well as multicast space (IPv4 224.0.0.0/4, IPv6 ff00::/8) +are always considered broadcast addresses and don't need to be declared. + +@cindex ConnectTo +@item ConnectTo = <@var{name}> +Specifies which other tinc daemon to connect to on startup. +Multiple ConnectTo variables may be specified, +in which case outgoing connections to each specified tinc daemon are made. +The names should be known to this tinc daemon +(i.e., there should be a host configuration file for the name on the ConnectTo line). + +If you don't specify a host with ConnectTo and don't enable AutoConnect, +tinc won't try to connect to other daemons at all, +and will instead just listen for incoming connections. + +@cindex DecrementTTL +@item DecrementTTL = (no) [experimental] +When enabled, tinc will decrement the Time To Live field in IPv4 packets, or the Hop Limit field in IPv6 packets, +before forwarding a received packet to the virtual network device or to another node, +and will drop packets that have a TTL value of zero, +in which case it will send an ICMP Time Exceeded packet back. + +Do not use this option if you use switch mode and want to use IPv6. + +@cindex Device +@item Device = <@var{device}> (@file{/dev/tap0}, @file{/dev/net/tun} or other depending on platform) +The virtual network device to use. +Tinc will automatically detect what kind of device it is. +Note that you can only use one device per daemon. +Under Windows, use @var{Interface} instead of @var{Device}. +Note that you can only use one device per daemon. +See also @ref{Device files}. + +@cindex DeviceStandby +@item DeviceStandby = (no) +When disabled, tinc calls @file{tinc-up} on startup, and @file{tinc-down} on shutdown. +When enabled, tinc will only call @file{tinc-up} when at least one node is reachable, +and will call @file{tinc-down} as soon as no nodes are reachable. +On Windows, this also determines when the virtual network interface "cable" is "plugged". + +@cindex DeviceType +@item DeviceType = <@var{type}> (platform dependent) +The type of the virtual network device. +Tinc will normally automatically select the right type of tun/tap interface, and this option should not be used. +However, this option can be used to select one of the special interface types, if support for them is compiled in. +@table @asis +@cindex dummy +@item dummy +Use a dummy interface. +No packets are ever read or written to a virtual network device. +Useful for testing, or when setting up a node that only forwards packets for other nodes. + +@cindex raw_socket +@item raw_socket +Open a raw socket, and bind it to a pre-existing +@var{Interface} (eth0 by default). +All packets are read from this interface. +Packets received for the local node are written to the raw socket. +However, at least on Linux, the operating system does not process IP packets destined for the local host. + +@cindex multicast +@item multicast +Open a multicast UDP socket and bind it to the address and port (separated by spaces) and optionally a TTL value specified using @var{Device}. +Packets are read from and written to this multicast socket. +This can be used to connect to UML, QEMU or KVM instances listening on the same multicast address. +Do NOT connect multiple tinc daemons to the same multicast address, this will very likely cause routing loops. +Also note that this can cause decrypted VPN packets to be sent out on a real network if misconfigured. + +@cindex UML +@item uml (not compiled in by default) +Create a UNIX socket with the filename specified by +@var{Device}, or @file{@value{localstatedir}/run/@var{netname}.umlsocket} +if not specified. +Tinc will wait for a User Mode Linux instance to connect to this socket. + +@cindex VDE +@item vde (not compiled in by default) +Uses the libvdeplug library to connect to a Virtual Distributed Ethernet switch, +using the UNIX socket specified by +@var{Device}, or @file{@value{localstatedir}/run/vde.ctl} +if not specified. +@end table -@c ================================================================== -@node Protocol Preview, The Meta-connection, The Connection, The Connection -@subsection A preview of the way the tinc works +Also, in case tinc does not seem to correctly interpret packets received from the virtual network device, +it can be used to change the way packets are interpreted: -@cindex ethertap -@cindex frame type -The data itself is read from a character device file, the so-called -@emph{ethertap} device. This device is associated with a network -interface. Any data sent to this interface can be read from the device, -and any data written to the device gets sent from the interface. Data to -and from the device is formatted as if it were a normal ethernet card, -so a frame is preceded by two MAC addresses and a @emph{frame type} -field. - -So when tinc reads an ethernet frame from the device, it determines its -type. Right now, tinc can only handle Internet Protocol version 4 (IPv4) -frames. Plans to support other protocols are being made. When tinc knows -which type of frame it has read, it can also read the source and -destination address from it. - -Now it is time that the frame gets encrypted. Currently the only -encryption algorithm available is blowfish. +@table @asis +@item tun (BSD and Linux) +Set type to tun. +Depending on the platform, this can either be with or without an address family header (see below). + +@cindex tunnohead +@item tunnohead (BSD) +Set type to tun without an address family header. +Tinc will expect packets read from the virtual network device to start with an IP header. +On some platforms IPv6 packets cannot be read from or written to the device in this mode. + +@cindex tunifhead +@item tunifhead (BSD) +Set type to tun with an address family header. +Tinc will expect packets read from the virtual network device +to start with a four byte header containing the address family, +followed by an IP header. +This mode should support both IPv4 and IPv6 packets. + +@cindex utun +@item utun (OS X) +Set type to utun. +This is only supported on OS X version 10.6.8 and higher, but doesn't require the tuntaposx module. +This mode should support both IPv4 and IPv6 packets. + +@item tap (BSD and Linux) +Set type to tap. +Tinc will expect packets read from the virtual network device +to start with an Ethernet header. +@end table -@cindex encapsulating -When the encryption is ready, time has come to actually transport the -packet to the destination computer. We do this by sending the packet -over an UDP connection to the destination host. This is called -@emph{encapsulating}, the VPN packet (though now encrypted) is -encapsulated in another IP datagram. +@cindex DirectOnly +@item DirectOnly = (no) [experimental] +When this option is enabled, packets that cannot be sent directly to the destination node, +but which would have to be forwarded by an intermediate node, are dropped instead. +When combined with the IndirectData option, +packets for nodes for which we do not have a meta connection with are also dropped. + +@cindex Ed25519PrivateKeyFile +@item Ed25519PrivateKeyFile = <@var{path}> (@file{@value{sysconfdir}/tinc/@var{netname}/ed25519_key.priv}) +The file in which the private Ed25519 key of this tinc daemon resides. +This is only used if ExperimentalProtocol is enabled. + +@cindex ExperimentalProtocol +@item ExperimentalProtocol = (yes) +When this option is enabled, the SPTPS protocol will be used when connecting to nodes that also support it. +Ephemeral ECDH will be used for key exchanges, +and Ed25519 will be used instead of RSA for authentication. +When enabled, an Ed25519 key must have been generated before with +@samp{tinc generate-ed25519-keys}. + +@cindex Forwarding +@item Forwarding = (internal) [experimental] +This option selects the way indirect packets are forwarded. -When the destination receives this packet, the same thing happens, only -in reverse. So it does a decrypt on the contents of the UDP datagram, -and it writes the decrypted information to its own ethertap device. +@table @asis +@item off +Incoming packets that are not meant for the local node, +but which should be forwarded to another node, are dropped. +@item internal +Incoming packets that are meant for another node are forwarded by tinc internally. -@c ================================================================== -@node The Meta-connection, , Protocol Preview, The Connection -@subsection The meta-connection +This is the default mode, and unless you really know you need another forwarding mode, don't change it. -Having only a UDP connection available is not enough. Though suitable -for transmitting data, we want to be able to reliably send other -information, such as routing and encryption information to somebody. +@item kernel +Incoming packets are always sent to the TUN/TAP device, even if the packets are not for the local node. +This is less efficient, but allows the kernel to apply its routing and firewall rules on them, +and can also help debugging. +@end table -TCP is a better alternative, because it already contains protection -against information being lost, unlike UDP. +@cindex Hostnames +@item Hostnames = (no) +This option selects whether IP addresses (both real and on the VPN) +should be resolved. Since DNS lookups are blocking, it might affect +tinc's efficiency, even stopping the daemon for a few seconds everytime +it does a lookup if your DNS server is not responding. + +This does not affect resolving hostnames to IP addresses from the +configuration file, but whether hostnames should be resolved while logging. + +@cindex Interface +@item Interface = <@var{interface}> +Defines the name of the interface corresponding to the virtual network device. +Depending on the operating system and the type of device this may or may not actually set the name of the interface. +Under Windows, this variable is used to select which network interface will be used. +If you specified a Device, this variable is almost always already correctly set. + +@cindex ListenAddress +@item ListenAddress = <@var{address}> [<@var{port}>] +If your computer has more than one IPv4 or IPv6 address, tinc +will by default listen on all of them for incoming connections. +This option can be used to restrict which addresses tinc listens on. +Multiple ListenAddress variables may be specified, +in which case listening sockets for each specified address are made. + +If no @var{port} is specified, the socket will listen on the port specified by the Port option, +or to port 655 if neither is given. +To only listen on a specific port but not to a specific address, use "*" for the @var{address}. + +@cindex LocalDiscovery +@item LocalDiscovery = (no) +When enabled, tinc will try to detect peers that are on the same local network. +This will allow direct communication using LAN addresses, even if both peers are behind a NAT +and they only ConnectTo a third node outside the NAT, +which normally would prevent the peers from learning each other's LAN address. + +Currently, local discovery is implemented by sending some packets to the local address of the node during UDP discovery. +This will not work with old nodes that don't transmit their local address. + +@cindex LocalDiscoveryAddress +@item LocalDiscoveryAddress <@var{address}> +If this variable is specified, local discovery packets are sent to the given @var{address}. + +@cindex Mode +@item Mode = (router) +This option selects the way packets are routed to other daemons. -So we establish two connections. One for the encrypted VPN data, and one -for other information, the meta-data. Hence, we call the second -connection the meta-connection. We can now be sure that the -meta-information doesn't get lost on the way to another computer. +@table @asis +@cindex router +@item router +In this mode Subnet +variables in the host configuration files will be used to form a routing table. +Only packets of routable protocols (IPv4 and IPv6) are supported in this mode. + +This is the default mode, and unless you really know you need another mode, don't change it. + +@cindex switch +@item switch +In this mode the MAC addresses of the packets on the VPN will be used to +dynamically create a routing table just like an Ethernet switch does. +Unicast, multicast and broadcast packets of every protocol that runs over Ethernet are supported in this mode +at the cost of frequent broadcast ARP requests and routing table updates. + +This mode is primarily useful if you want to bridge Ethernet segments. + +@cindex hub +@item hub +This mode is almost the same as the switch mode, but instead +every packet will be broadcast to the other daemons +while no routing table is managed. +@end table -@cindex data-protocol -@cindex meta-protocol -Like with any communication, we must have a protocol, so that everybody -knows what everything stands for, an how he should react. Because we -have two connections, we also have two protocols. The protocol used for -the UDP data is the ``data-protocol,'' the other one is the -``meta-protocol.'' +@cindex KeyExpire +@item KeyExpire = <@var{seconds}> (3600) +This option controls the time the encryption keys used to encrypt the data +are valid. It is common practice to change keys at regular intervals to +make it even harder for crackers, even though it is thought to be nearly +impossible to crack a single key. + +@cindex MACExpire +@item MACExpire = <@var{seconds}> (600) +This option controls the amount of time MAC addresses are kept before they are removed. +This only has effect when Mode is set to "switch". + +@cindex MaxConnectionBurst +@item MaxConnectionBurst = <@var{count}> (100) +This option controls how many connections tinc accepts in quick succession. +If there are more connections than the given number in a short time interval, +tinc will reduce the number of accepted connections to only one per second, +until the burst has passed. + +@cindex Name +@item Name = <@var{name}> [required] +This is a symbolic name for this connection. +The name must consist only of alfanumeric and underscore characters (a-z, A-Z, 0-9 and _), and is case sensitive. + +If Name starts with a $, then the contents of the environment variable that follows will be used. +In that case, invalid characters will be converted to underscores. +If Name is $HOST, but no such environment variable exist, +the hostname will be read using the gethostname() system call. + +@cindex PingInterval +@item PingInterval = <@var{seconds}> (60) +The number of seconds of inactivity that tinc will wait before sending a +probe to the other end. + +@cindex PingTimeout +@item PingTimeout = <@var{seconds}> (5) +The number of seconds to wait for a response to pings or to allow meta +connections to block. If the other end doesn't respond within this time, +the connection is terminated, and the others will be notified of this. + +@cindex PriorityInheritance +@item PriorityInheritance = (no) [experimental] +When this option is enabled the value of the TOS field of tunneled IPv4 packets +will be inherited by the UDP packets that are sent out. + +@cindex PrivateKey +@item PrivateKey = <@var{key}> [obsolete] +This is the RSA private key for tinc. However, for safety reasons it is +advised to store private keys of any kind in separate files. This prevents +accidental eavesdropping if you are editting the configuration file. + +@cindex PrivateKeyFile +@item PrivateKeyFile = <@var{path}> (@file{@value{sysconfdir}/tinc/@var{netname}/rsa_key.priv}) +This is the full path name of the RSA private key file that was +generated by @samp{tinc generate-keys}. It must be a full path, not a +relative directory. + +@cindex ProcessPriority +@item ProcessPriority = +When this option is used the priority of the tincd process will be adjusted. +Increasing the priority may help to reduce latency and packet loss on the VPN. + +@cindex Proxy +@item Proxy = socks4 | socks5 | http | exec @var{...} [experimental] +Use a proxy when making outgoing connections. +The following proxy types are currently supported: +@table @asis +@cindex socks4 +@item socks4 <@var{address}> <@var{port}> [<@var{username}>] +Connects to the proxy using the SOCKS version 4 protocol. +Optionally, a @var{username} can be supplied which will be passed on to the proxy server. + +@cindex socks5 +@item socks5 <@var{address}> <@var{port}> [<@var{username}> <@var{password}>] +Connect to the proxy using the SOCKS version 5 protocol. +If a @var{username} and @var{password} are given, basic username/password authentication will be used, +otherwise no authentication will be used. + +@cindex http +@item http <@var{address}> <@var{port}> +Connects to the proxy and sends a HTTP CONNECT request. + +@cindex exec +@item exec <@var{command}> +Executes the given command which should set up the outgoing connection. +The environment variables @env{NAME}, @env{NODE}, @env{REMOTEADDRES} and @env{REMOTEPORT} are available. +@end table -@c ================================================================== -@node Security, The Protocol, The Connection, Technical information -@section About tinc's encryption and other security-related issues. +@cindex ReplayWindow +@item ReplayWindow = (32) +This is the size of the replay tracking window for each remote node, in bytes. +The window is a bitfield which tracks 1 packet per bit, so for example +the default setting of 32 will track up to 256 packets in the window. In high +bandwidth scenarios, setting this to a higher value can reduce packet loss from +the interaction of replay tracking with underlying real packet loss and/or +reordering. Setting this to zero will disable replay tracking completely and +pass all traffic, but leaves tinc vulnerable to replay-based attacks on your +traffic. + +@cindex StrictSubnets +@item StrictSubnets = (no) [experimental] +When this option is enabled tinc will only use Subnet statements which are +present in the host config files in the local +@file{@value{sysconfdir}/tinc/@var{netname}/hosts/} directory. +Subnets learned via connections to other nodes and which are not +present in the local host config files are ignored. + +@cindex TunnelServer +@item TunnelServer = (no) [experimental] +When this option is enabled tinc will no longer forward information between other tinc daemons, +and will only allow connections with nodes for which host config files are present in the local +@file{@value{sysconfdir}/tinc/@var{netname}/hosts/} directory. +Setting this options also implicitly sets StrictSubnets. + +@cindex UDPDiscovey +@item UDPDiscovery = (yes) +When this option is enabled tinc will try to establish UDP connectivity to nodes, +using TCP while it determines if a node is reachable over UDP. If it is disabled, +tinc always assumes a node is reachable over UDP. +Note that tinc will never use UDP with nodes that have TCPOnly enabled. + +@cindex UDPDiscoveryKeepaliveInterval +@item UDPDiscoveryKeepaliveInterval = (9) +The minimum amount of time between sending UDP ping datagrams to check UDP connectivity once it has been established. +Note that these pings are large, since they are used to verify link MTU as well. + +@cindex UDPDiscoveryInterval +@item UDPDiscoveryInterval = (2) +The minimum amount of time between sending UDP ping datagrams to try to establish UDP connectivity. + +@cindex UDPDiscoveryTimeout +@item UDPDiscoveryTimeout = (30) +If tinc doesn't receive any UDP ping replies over the specified interval, +it will assume UDP communication is broken and will fall back to TCP. + +@cindex UDPInfoInterval +@item UDPInfoInterval = (5) +The minimum amount of time between sending periodic updates about UDP addresses, which are mostly useful for UDP hole punching. + +@cindex UDPRcvBuf +@item UDPRcvBuf = (1048576) +Sets the socket receive buffer size for the UDP socket, in bytes. +If set to zero, the default buffer size will be used by the operating system. +Note: this setting can have a significant impact on performance, especially raw throughput. + +@cindex UDPSndBuf +@item UDPSndBuf = (1048576) +Sets the socket send buffer size for the UDP socket, in bytes. +If set to zero, the default buffer size will be used by the operating system. +Note: this setting can have a significant impact on performance, especially raw throughput. + +@cindex UPnP +@item UPnP = (no) +If this option is enabled then tinc will search for UPnP-IGD devices on the local network. +It will then create and maintain port mappings for tinc's listening TCP and UDP ports. +If set to "udponly", tinc will only create a mapping for its UDP (data) port, not for its TCP (metaconnection) port. +Note that tinc must have been built with miniupnpc support for this feature to be available. +Furthermore, be advised that enabling this can have security implications, because the miniupnpc library that +tinc uses might not be well-hardened with regard to malicious UPnP replies. + +@cindex UPnPDiscoverWait +@item UPnPDiscoverWait = (5) +The amount of time to wait for replies when probing the local network for UPnP devices. + +@cindex UPnPRefreshPeriod +@item UPnPRefreshPeriod = (5) +How often tinc will re-add the port mapping, in case it gets reset on the UPnP device. +This also controls the duration of the port mapping itself, which will be set to twice that duration. -@cindex tinc -@cindex Cabal -tinc got its name from ``TINC,'' short for @emph{There Is No Cabal}; the -alleged Cabal was/is an organization that was said to keep an eye on the -entire Internet. As this is exactly what you @emph{don't} want, we named -the tinc project after TINC. +@end table -@cindex SVPN -But in order to be ``immune'' to eavesdropping, you'll have to encrypt -your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does -exactly that: encrypt. -This chapter is a mixture of ideas, reasoning and explanation, please -don't take it too serious. +@c ================================================================== +@node Host configuration variables +@subsection Host configuration variables -@menu -* Key Management:: -* Authentication:: -* Protection:: -@end menu +@table @asis +@cindex Address +@item Address = <@var{IP address}|@var{hostname}> [] [recommended] +This variable is only required if you want to connect to this host. It +must resolve to the external IP address where the host can be reached, +not the one that is internal to the VPN. +If no port is specified, the default Port is used. +Multiple Address variables can be specified, in which case each address will be +tried until a working connection has been established. + +@cindex Cipher +@item Cipher = <@var{cipher}> (blowfish) +The symmetric cipher algorithm used to encrypt UDP packets using the legacy protocol. +Any cipher supported by LibreSSL or OpenSSL is recognized. +Furthermore, specifying "none" will turn off packet encryption. +It is best to use only those ciphers which support CBC mode. +This option has no effect for connections using the SPTPS protocol, which always use AES-256-CTR. + +@cindex ClampMSS +@item ClampMSS = (yes) +This option specifies whether tinc should clamp the maximum segment size (MSS) +of TCP packets to the path MTU. This helps in situations where ICMP +Fragmentation Needed or Packet too Big messages are dropped by firewalls. + +@cindex Compression +@item Compression = <@var{level}> (0) +This option sets the level of compression used for UDP packets. +Possible values are 0 (off), 1 (fast zlib) and any integer up to 9 (best zlib), +10 (fast lzo) and 11 (best lzo). + +@cindex Digest +@item Digest = <@var{digest}> (sha1) +The digest algorithm used to authenticate UDP packets using the legacy protocol. +Any digest supported by LibreSSL or OpenSSL is recognized. +Furthermore, specifying "none" will turn off packet authentication. +This option has no effect for connections using the SPTPS protocol, which always use HMAC-SHA-256. + +@cindex IndirectData +@item IndirectData = (no) +When set to yes, other nodes which do not already have a meta connection to you +will not try to establish direct communication with you. +It is best to leave this option out or set it to no. + +@cindex MACLength +@item MACLength = <@var{bytes}> (4) +The length of the message authentication code used to authenticate UDP packets using the legacy protocol. +Can be anything from 0 +up to the length of the digest produced by the digest algorithm. +This option has no effect for connections using the SPTPS protocol, which never truncate MACs. + +@cindex PMTU +@item PMTU = <@var{mtu}> (1514) +This option controls the initial path MTU to this node. + +@cindex PMTUDiscovery +@item PMTUDiscovery = (yes) +When this option is enabled, tinc will try to discover the path MTU to this node. +After the path MTU has been discovered, it will be enforced on the VPN. + +@cindex MTUInfoInterval +@item MTUInfoInterval = (5) +The minimum amount of time between sending periodic updates about relay path MTU. Useful for quickly determining MTU to indirect nodes. + +@cindex Port +@item Port = <@var{port}> (655) +This is the port this tinc daemon listens on. +You can use decimal portnumbers or symbolic names (as listed in @file{/etc/services}). + +@cindex PublicKey +@item PublicKey = <@var{key}> [obsolete] +This is the RSA public key for this host. + +@cindex PublicKeyFile +@item PublicKeyFile = <@var{path}> [obsolete] +This is the full path name of the RSA public key file that was generated +by @samp{tinc generate-keys}. It must be a full path, not a relative +directory. + +@cindex PEM format +From version 1.0pre4 on tinc will store the public key directly into the +host configuration file in PEM format, the above two options then are not +necessary. Either the PEM format is used, or exactly +@strong{one of the above two options} must be specified +in each host configuration file, if you want to be able to establish a +connection with that host. + +@cindex Subnet +@item Subnet = <@var{address}[/@var{prefixlength}[#@var{weight}]]> +The subnet which this tinc daemon will serve. +Tinc tries to look up which other daemon it should send a packet to by searching the appropiate subnet. +If the packet matches a subnet, +it will be sent to the daemon who has this subnet in his host configuration file. +Multiple subnet lines can be specified for each daemon. + +Subnets can either be single MAC, IPv4 or IPv6 addresses, +in which case a subnet consisting of only that single address is assumed, +or they can be a IPv4 or IPv6 network address with a prefixlength. +For example, IPv4 subnets must be in a form like 192.168.1.0/24, +where 192.168.1.0 is the network address and 24 is the number of bits set in the netmask. +Note that subnets like 192.168.1.1/24 are invalid! +Read a networking HOWTO/FAQ/guide if you don't understand this. +IPv6 subnets are notated like fec0:0:0:1::/64. +MAC addresses are notated like 0:1a:2b:3c:4d:5e. + +@cindex CIDR notation +Prefixlength is the number of bits set to 1 in the netmask part; for +example: netmask 255.255.255.0 would become /24, 255.255.252.0 becomes +/22. This conforms to standard CIDR notation as described in +@uref{https://www.ietf.org/rfc/rfc1519.txt, RFC1519} + +A Subnet can be given a weight to indicate its priority over identical Subnets +owned by different nodes. The default weight is 10. Lower values indicate +higher priority. Packets will be sent to the node with the highest priority, +unless that node is not reachable, in which case the node with the next highest +priority will be tried, and so on. + +@cindex TCPonly +@item TCPonly = (no) +If this variable is set to yes, then the packets are tunnelled over a +TCP connection instead of a UDP connection. This is especially useful +for those who want to run a tinc daemon from behind a masquerading +firewall, or if UDP packet routing is disabled somehow. +Setting this options also implicitly sets IndirectData. + +@cindex Weight +@item Weight = +If this variable is set, it overrides the weight given to connections made with +another host. A higher weight means a lower priority is given to this +connection when broadcasting or forwarding packets. +@end table @c ================================================================== -@node Key Management, Authentication, Security, Security -@subsection Key Management -@c FIXME: recheck +@node Scripts +@subsection Scripts -@cindex Diffie-Hellman -You can't just send a private encryption key to your peer, because -somebody else might already be listening to you. So you'll have to -negotiate over a shared but secret key. One way to do this is by using -the ``Diffie-Hellman key exchange'' protocol -(@uref{http://www.rsa.com/rsalabs/faq/html/3-6-1.html}). The idea is as -follows. +@cindex scripts +Apart from reading the server and host configuration files, +tinc can also run scripts at certain moments. +Below is a list of filenames of scripts and a description of when they are run. +A script is only run if it exists and if it is executable. -You have two participants A and B that want to agree over a shared -secret encryption key. Both parties have some large prime number p and a -generator g. These numbers may be known to the outside world, and hence -may be included in the source distribution. +Scripts are run synchronously; +this means that tinc will temporarily stop processing packets until the called script finishes executing. +This guarantees that scripts will execute in the exact same order as the events that trigger them. +If you need to run commands asynchronously, you have to ensure yourself that they are being run in the background. -@cindex secret key -Both parties then generate a secret key. A generates a, and computes g^a -mod p. This is then sent to B; while B computes g^b mod p, and transmits -this to A, b being generated by B. Both a and b must be smaller than -p-1. +Under Windows (not Cygwin), the scripts should have the extension @file{.bat} or @file{.cmd}. -These private keys are generated upon startup, and they are not changed -while the connection exists. A possible feature in the future is to -dynamically change the keys, every hour for example. +@table @file +@cindex tinc-up +@item @value{sysconfdir}/tinc/@var{netname}/tinc-up +This is the most important script. +If it is present it will be executed right after the tinc daemon has been +started and has connected to the virtual network device. +It should be used to set up the corresponding network interface, +but can also be used to start other things. -Both parties then calculate g^ab mod p = k. k is the new, shared, but -still secret key. +Under Windows you can use the Network Connections control panel instead of creating this script. -To obtain a key k of a sufficient length (128 bits in our vpnd), p -should be 2^129-1 or more. +@cindex tinc-down +@item @value{sysconfdir}/tinc/@var{netname}/tinc-down +This script is started right before the tinc daemon quits. +@item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-up +This script is started when the tinc daemon with name @var{host} becomes reachable. -@c ================================================================== -@node Authentication, Protection, Key Management, Security -@subsection Authentication -@c FIXME: recheck +@item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-down +This script is started when the tinc daemon with name @var{host} becomes unreachable. -@cindex man-in-the-middle attack -Because the Diffie-Hellman protocol is in itself vulnerable to the -``man-in-the-middle attack,'' we should introduce an authentication -system. +@item @value{sysconfdir}/tinc/@var{netname}/host-up +This script is started when any host becomes reachable. -We will let A transmit a passphrase that is also known to B encrypted -with g^a, before A sends this to B. This way, B can check whether A is -really A or just someone else. +@item @value{sysconfdir}/tinc/@var{netname}/host-down +This script is started when any host becomes unreachable. -@cindex passphrase -This passphrase should be 2304 bits for a symmetric encryption -system. But since an asymmetric system is more secure, we could do with -2048 bits. This only holds if the passphrase is very random. +@item @value{sysconfdir}/tinc/@var{netname}/subnet-up +This script is started when a Subnet becomes reachable. +The Subnet and the node it belongs to are passed in environment variables. -These passphrases could be stored in a file that is non-readable by -anyone else but root; e.g. @file{/etc/vpn/passphrases}. +@item @value{sysconfdir}/tinc/@var{netname}/subnet-down +This script is started when a Subnet becomes unreachable. -The only thing that needs to be taken care of is how A announces its -passphrase to B. +@item @value{sysconfdir}/tinc/@var{netname}/invitation-created +This script is started when a new invitation has been created. +@item @value{sysconfdir}/tinc/@var{netname}/invitation-accepted +This script is started when an invitation has been used. -@c ================================================================== -@node Protection, , Authentication, Security -@subsection Protecting your data +@end table -Now we have securely hidden our data. But a malicious cracker may still -bother you by randomly altering the encrypted data he intercepts. +@cindex environment variables +The scripts are started without command line arguments, +but can make use of certain environment variables. +Under UNIX like operating systems the names of environment variables must be preceded by a $ in scripts. +Under Windows, in @file{.bat} or @file{.cmd} files, they have to be put between % signs. + +@table @env +@cindex NETNAME +@item NETNAME +If a netname was specified, this environment variable contains it. + +@cindex NAME +@item NAME +Contains the name of this tinc daemon. + +@cindex DEVICE +@item DEVICE +Contains the name of the virtual network device that tinc uses. + +@cindex INTERFACE +@item INTERFACE +Contains the name of the virtual network interface that tinc uses. +This should be used for commands like ifconfig. + +@cindex NODE +@item NODE +When a host becomes (un)reachable, this is set to its name. +If a subnet becomes (un)reachable, this is set to the owner of that subnet. + +@cindex REMOTEADDRESS +@item REMOTEADDRESS +When a host becomes (un)reachable, this is set to its real address. + +@cindex REMOTEPORT +@item REMOTEPORT +When a host becomes (un)reachable, +this is set to the port number it uses for communication with other tinc daemons. + +@cindex SUBNET +@item SUBNET +When a subnet becomes (un)reachable, this is set to the subnet. + +@cindex WEIGHT +@item WEIGHT +When a subnet becomes (un)reachable, this is set to the subnet weight. + +@cindex INVITATION_FILE +@item INVITATION_FILE +When the @file{invitation-created} script is called, +this is set to the file where the invitation details will be stored. + +@cindex INVITATION_URL +@item INVITATION_URL +When the @file{invitation-created} script is called, +this is set to the invitation URL that has been created. +@end table +Do not forget that under UNIX operating systems, +you have to make the scripts executable, using the command @samp{chmod a+x script}. -@c ================================================================== -@node The Protocol, , Security, Technical information -@section Detailed protocol specifications +@c ================================================================== +@node How to configure +@subsection How to configure +@subsubheading Step 1. Creating initial configuration files. -@menu -* Data protocol:: -* Meta protocol:: -@end menu +The initial directory structure, configuration files and public/private keypairs are created using the following command: -@c ================================================================== -@node Data protocol, Meta protocol, The Protocol, The Protocol -@subsection The data protocol +@example +tinc -n @var{netname} init @var{name} +@end example -The data that is sent through the UDP connection is formatted as follows: +(You will need to run this as root, or use "sudo".) +This will create the configuration directory @file{@value{sysconfdir}/tinc/@var{netname}.}, +and inside it will create another directory named @file{hosts/}. +In the configuration directory, it will create the file @file{tinc.conf} with the following contents: @example +Name = @var{name} +@end example - bytes | Contents ----------------------- - 0-1 | The length of this packet, including all leading fields - 2-5 | The destination IP address - 6-... | The encrypted data +It will also create private RSA and Ed25519 keys, which will be stored in the files @file{rsa_key.priv} and @file{ed25519_key.priv}. +It will also create a host configuration file @file{hosts/@var{name}}, +which will contain the corresponding public RSA and Ed25519 keys. -@end example +Finally, on UNIX operating systems, it will create an executable script @file{tinc-up}, +which will initially not do anything except warning that you should edit it. -The method that was used to encrypt the data should be made known via -the meta-protocol, during early identification stages. +@subsubheading Step 2. Modifying the initial configuration. +Unless you want to use tinc in switch mode, +you should now configure which range of addresses you will use on the VPN. +Let's assume you will be part of a VPN which uses the address range 192.168.0.0/16, +and you yourself have a smaller portion of that range: 192.168.2.0/24. +Then you should run the following command: -@c ================================================================== -@node Meta protocol, , Data protocol, The Protocol -@subsection The Meta protocol +@example +tinc -n @var{netname} add subnet 192.168.2.0/24 +@end example -This protocol consists of separate packets of information, that are -generally formatted thusly: +This will add a Subnet statement to your host configuration file. +Try opening the file @file{@value{sysconfdir}/tinc/@var{netname}/hosts/@var{name}} in an editor. +You should now see a file containing the public RSA and Ed25519 keys (which looks like a bunch of random characters), +and the following line at the bottom: @example +Subnet = 192.168.2.0/24 +@end example - bytes | Contents ----------------------- - 0 | The request ID - 1-... | (Optional: arguments) +If you will use more than one address range, you can add more Subnets. +For example, if you also use the IPv6 subnet fec0:0:0:2::/64, you can add it as well: +@example +tinc -n @var{netname} add subnet fec0:0:0:2::/24 @end example -What follows is a listing of possible request IDs. +This will add another line to the file @file{hosts/@var{name}}. +If you make a mistake, you can undo it by simply using @samp{del} instead of @samp{add}. -@table @samp -@item ACK -Acknowledge. This generally means that the authentication has been -accepted by the remote computer. Takes no arguments. +If you want other tinc daemons to create meta-connections to your daemon, +you should add your public IP address or hostname to your host configuration file. +For example, if your hostname is foo.example.org, run: @example +tinc -n @var{netname} add address foo.example.org +@end example - bytes | Contents ----------------------- - 0 | `1' +If you already know to which daemons your daemon should make meta-connections, +you should configure that now as well. +Suppose you want to connect to a daemon named "bar", run: +@example +tinc -n @var{netname} add connectto bar @end example -@item AUTH_S_INIT -@itemx AUTH_C_INIT -Obsolete. Use @samp{BASIC_INFO}. +Note that you specify the Name of the other daemon here, not an IP address or hostname! +When you start tinc, and it tries to make a connection to "bar", +it will look for a host configuration file named @file{hosts/bar}, +and will read Address statements and public keys from that file. -@item AUTH_S_SPP -@itemx AUTH_C_SPP -Obsolete. Use @samp{PASSPHRASE}. +@subsubheading Step 2. Exchanging configuration files. -@item AUTH_S_SKEY -@itemx AUTH_C_SKEY -Obsolete. Use @samp{PUBLIC_KEY}, @samp{REQ_KEY} and @samp{ANS_KEY}. +If your daemon has a ConnectTo = bar statement in its @file{tinc.conf} file, +or if bar has a ConnectTo your daemon, then you both need each other's host configuration files. +You should send @file{hosts/@var{name}} to bar, and bar should send you his file which you should move to @file{hosts/bar}. +If you are on a UNIX platform, you can easily send an email containing the necessary information using the following command +(assuming the owner of bar has the email address bar@@example.org): -@item AUTH_S_SACK -@itemx AUTH_C_RACK -Obsolete. Use @samp{ACK}. +@example +tinc -n @var{netname} export | mail -s "My config file" bar@@example.org +@end example -@item TERMREQ -A request to terminate this connection, for whatever reason. +If the owner of bar does the same to send his host configuration file to you, +you can probably pipe his email through the following command, +or you can just start this command in a terminal and copy&paste the email: @example +tinc -n @var{netname} import +@end example - bytes | Contents ----------------------- - 0 | `30' - 1-4 | The VPN IP address of the host that has exited +If you are the owner of bar yourself, and you have SSH access to that computer, +you can also swap the host configuration files using the following command: +@example +tinc -n @var{netname} export \ + | ssh bar.example.org tinc -n @var{netname} exchange \ + | tinc -n @var{netname} import @end example +You should repeat this for all nodes you ConnectTo, or which ConnectTo you. +However, remember that you do not need to ConnectTo all nodes in the VPN; +it is only necessary to create one or a few meta-connections, +after the connections are made tinc will learn about all the other nodes in the VPN, +and will automatically make other connections as necessary. -@item PINGTIMEOUT -Terminate connection, but the reason must be a ping timeout. -@example +@c ================================================================== +@node Network interfaces +@section Network interfaces - bytes | Contents ----------------------- - 0 | `31' - 1-4 | The VPN IP address of the host that has exited +Before tinc can start transmitting data over the tunnel, it must +set up the virtual network interface. -@end example +First, decide which IP addresses you want to have associated with these +devices, and what network mask they must have. +Tinc will open a virtual network device (@file{/dev/tun}, @file{/dev/tap0} or similar), +which will also create a network interface called something like @samp{tun0}, @samp{tap0}. +If you are using the Linux tun/tap driver, the network interface will by default have the same name as the @var{netname}. +Under Windows you can change the name of the network interface from the Network Connections control panel. -@item PING -Send probe to the other end, if he hasn't returned a @samp{PONG} within -10 seconds, the connection is considered to be dead and will be -terminated, we should try to notify the other by sending a -@samp{PINGTIMEOUT} packet. +@cindex tinc-up +You can configure the network interface by putting ordinary ifconfig, route, and other commands +to a script named @file{@value{sysconfdir}/tinc/@var{netname}/tinc-up}. +When tinc starts, this script will be executed. When tinc exits, it will execute the script named +@file{@value{sysconfdir}/tinc/@var{netname}/tinc-down}, but normally you don't need to create that script. +You can manually open the script in an editor, or use the following command: @example +tinc -n @var{netname} edit tinc-up +@end example - bytes | Contents ----------------------- - 0 | `40' +An example @file{tinc-up} script, that would be appropriate for the scenario in the previous section, is: +@example +#!/bin/sh +ifconfig $INTERFACE 192.168.2.1 netmask 255.255.0.0 +ip addr add fec0:0:0:2::/48 dev $INTERFACE @end example +The first command gives the interface an IPv4 address and a netmask. +The kernel will also automatically add an IPv4 route to this interface, so normally you don't need +to add route commands to the @file{tinc-up} script. +The kernel will also bring the interface up after this command. +@cindex netmask +The netmask is the mask of the @emph{entire} VPN network, not just your +own subnet. +The second command gives the interface an IPv6 address and netmask, +which will also automatically add an IPv6 route. +If you only want to use "ip addr" commands on Linux, don't forget that it doesn't bring the interface up, unlike ifconfig, +so you need to add @samp{ip link set $INTERFACE up} in that case. -@item PONG -See explanation for @samp{PING} +The exact syntax of the ifconfig and route commands differs from platform to platform. +You can look up the commands for setting addresses and adding routes in @ref{Platform specific information}, +but it is best to consult the manpages of those utilities on your platform. -@example - bytes | Contents ----------------------- - 0 | `41' +@c ================================================================== +@node Example configuration +@section Example configuration -@end example +@cindex example +Imagine the following situation. Branch A of our example `company' wants to connect +three branch offices in B, C and D using the Internet. All four offices +have a 24/7 connection to the Internet. -@item ADD_HOST -Send an @samp{ADD_HOST} packet if you want to propagate all your current -connections to a new computer on a network. If we get this request, we -must forward it to everyone that hasn't got it yet. +A is going to serve as the center of the network. B and C will connect +to A, and D will connect to C. Each office will be assigned their own IP +network, 10.x.0.0. @example - - bytes | Contents ----------------------- - 0 | `60' - 1-4 | The real IP address of the new host - 5-8 | The VPN IP address of the new host - 9-12 | The VPN netmask - 13-14 | The port number that the new host listens on - +A: net 10.1.0.0 mask 255.255.0.0 gateway 10.1.54.1 internet IP 1.2.3.4 +B: net 10.2.0.0 mask 255.255.0.0 gateway 10.2.1.12 internet IP 2.3.4.5 +C: net 10.3.0.0 mask 255.255.0.0 gateway 10.3.69.254 internet IP 3.4.5.6 +D: net 10.4.0.0 mask 255.255.0.0 gateway 10.4.3.32 internet IP 4.5.6.7 @end example +Here, ``gateway'' is the VPN IP address of the machine that is running the +tincd, and ``internet IP'' is the IP address of the firewall, which does not +need to run tincd, but it must do a port forwarding of TCP and UDP on port +655 (unless otherwise configured). -@item BASIC_INFO -This packet will contain all necessary basic information about -ourselves, such as the port we listen on and our desired VPN IP address. - -@example +In this example, it is assumed that eth0 is the interface that points to +the inner (physical) LAN of the office, although this could also be the +same as the interface that leads to the Internet. The configuration of +the real interface is also shown as a comment, to give you an idea of +how these example host is set up. All branches use the netname `company' +for this particular VPN. - bytes | Contents ----------------------- - 0 | `61' - 1 | The protocol version. - | This chapter describes version 4. - 2-3 | The port number that the new host listens on - 4-7 | The VPN IP address of the new host - 8-11 | The VPN netmask +Each branch is set up using the @samp{tinc init} and @samp{tinc config} commands, +here we just show the end results: -@end example +@subsubheading For Branch A +@emph{BranchA} would be configured like this: -@item PASSPHRASE -Send an encrypted passphrase. Should be encrypted with our -@strong{public} key, and it must reach us before a @samp{PUBLIC_KEY} -request. +In @file{@value{sysconfdir}/tinc/company/tinc-up}: @example +#!/bin/sh - bytes | Contents ----------------------- - 0 | `62' - 1-2 | The length of the encrypted passphrase - 3-... | The encrypted passphrase +# Real interface of internal network: +# ifconfig eth0 10.1.54.1 netmask 255.255.0.0 +ifconfig $INTERFACE 10.1.54.1 netmask 255.0.0.0 @end example - -@item PUBLIC_KEY -This is only used during authentication of a new connection, later on we -may use @samp{REQ_KEY} and @samp{ANS_KEY}. +and in @file{@value{sysconfdir}/tinc/company/tinc.conf}: @example +Name = BranchA +@end example + +On all hosts, @file{@value{sysconfdir}/tinc/company/hosts/BranchA} contains: - bytes | Contents ----------------------- - 0 | `63' - 1-2 | The length of the key - 3-... | The public key, given in base-36 +@example +Subnet = 10.1.0.0/16 +Address = 1.2.3.4 +-----BEGIN RSA PUBLIC KEY----- +... +-----END RSA PUBLIC KEY----- @end example +Note that the IP addresses of eth0 and the VPN interface are the same. +This is quite possible, if you make sure that the netmasks of the interfaces are different. +It is in fact recommended to give both real internal network interfaces and VPN interfaces the same IP address, +since that will make things a lot easier to remember and set up. + + +@subsubheading For Branch B + +In @file{@value{sysconfdir}/tinc/company/tinc-up}: -@item HOLD -@itemx RESUME -Unused. +@example +#!/bin/sh + +# Real interface of internal network: +# ifconfig eth0 10.2.43.8 netmask 255.255.0.0 -@item CALCULATE -@itemx CALC_RES -@itemx ALMOST_KEY -Never been in use. +ifconfig $INTERFACE 10.2.1.12 netmask 255.0.0.0 +@end example -@item REQ_KEY -Request a public key from someone and return it to the sender of this -request using a @samp{ANS_KEY} packet. If we get such request, we must -forward it to the connection that leads to the destination. +and in @file{@value{sysconfdir}/tinc/company/tinc.conf}: @example +Name = BranchB +ConnectTo = BranchA +@end example + +Note here that the internal address (on eth0) doesn't have to be the +same as on the VPN interface. Also, ConnectTo is given so that this node will +always try to connect to BranchA. - bytes | Contents ----------------------- - 0 | `160' - 1-4 | The source VPN IP address - 5-8 | The destination VPN IP address - 9-14 | `0' +On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchB}: +@example +Subnet = 10.2.0.0/16 +Address = 2.3.4.5 + +-----BEGIN RSA PUBLIC KEY----- +... +-----END RSA PUBLIC KEY----- @end example -@item ANS_KEY -Answer to a @samp{REQ_KEY} request, forward it to the destination if it -is not meant for us. +@subsubheading For Branch C + +In @file{@value{sysconfdir}/tinc/company/tinc-up}: @example +#!/bin/sh + +# Real interface of internal network: +# ifconfig eth0 10.3.69.254 netmask 255.255.0.0 + +ifconfig $INTERFACE 10.3.69.254 netmask 255.0.0.0 +@end example - bytes | Contents ----------------------- - 0 | `161' - 1-4 | The source VPN IP address - 5-8 | The destination VPN IP address - 9-12 | The expiration date/time in seconds - 13-14 | The key length - 15-... | The public key in base-36 +and in @file{@value{sysconfdir}/tinc/company/tinc.conf}: +@example +Name = BranchC +ConnectTo = BranchA @end example +C already has another daemon that runs on port 655, so they have to +reserve another port for tinc. It knows the portnumber it has to listen on +from it's own host configuration file. + +On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchC}: + +@example +Address = 3.4.5.6 +Subnet = 10.3.0.0/16 +Port = 2000 + +-----BEGIN RSA PUBLIC KEY----- +... +-----END RSA PUBLIC KEY----- +@end example + + +@subsubheading For Branch D + +In @file{@value{sysconfdir}/tinc/company/tinc-up}: + +@example +#!/bin/sh + +# Real interface of internal network: +# ifconfig eth0 10.4.3.32 netmask 255.255.0.0 + +ifconfig $INTERFACE 10.4.3.32 netmask 255.0.0.0 +@end example + +and in @file{@value{sysconfdir}/tinc/company/tinc.conf}: + +@example +Name = BranchD +ConnectTo = BranchC +@end example + +D will be connecting to C, which has a tincd running for this network on +port 2000. It knows the port number from the host configuration file. + +On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchD}: + +@example +Subnet = 10.4.0.0/16 +Address = 4.5.6.7 + +-----BEGIN RSA PUBLIC KEY----- +... +-----END RSA PUBLIC KEY----- +@end example + +@subsubheading Key files + +A, B, C and D all have their own public/private keypairs: + +The private RSA key is stored in @file{@value{sysconfdir}/tinc/company/rsa_key.priv}, +the private Ed25519 key is stored in @file{@value{sysconfdir}/tinc/company/ed25519_key.priv}, +and the public RSA and Ed25519 keys are put into the host configuration file in the @file{@value{sysconfdir}/tinc/company/hosts/} directory. + +@subsubheading Starting + +After each branch has finished configuration and they have distributed +the host configuration files amongst them, they can start their tinc daemons. +They don't necessarily have to wait for the other branches to have started +their daemons, tinc will try connecting until they are available. + + +@c ================================================================== +@node Running tinc +@chapter Running tinc + +If everything else is done, you can start tinc by typing the following command: + +@example +tinc -n @var{netname} start +@end example + +@cindex daemon +Tinc will detach from the terminal and continue to run in the background like a good daemon. +If there are any problems however you can try to increase the debug level +and look in the syslog to find out what the problems are. + +@menu +* Runtime options:: +* Signals:: +* Debug levels:: +* Solving problems:: +* Error messages:: +* Sending bug reports:: +@end menu + + +@c ================================================================== +@node Runtime options +@section Runtime options + +Besides the settings in the configuration file, tinc also accepts some +command line options. + +@cindex command line +@cindex runtime options +@cindex options +@c from the manpage +@table @option +@item -c, --config=@var{path} +Read configuration options from the directory @var{path}. The default is +@file{@value{sysconfdir}/tinc/@var{netname}/}. + +@item -D, --no-detach +Don't fork and detach. +This will also disable the automatic restart mechanism for fatal errors. + +@cindex debug level +@item -d, --debug=@var{level} +Set debug level to @var{level}. The higher the debug level, the more gets +logged. Everything goes via syslog. + +@item -n, --net=@var{netname} +Use configuration for net @var{netname}. +This will let tinc read all configuration files from +@file{@value{sysconfdir}/tinc/@var{netname}/}. +Specifying . for @var{netname} is the same as not specifying any @var{netname}. +@xref{Multiple networks}. + +@item --pidfile=@var{filename} +Store a cookie in @var{filename} which allows tinc to authenticate. +If unspecified, the default is +@file{@value{localstatedir}/run/tinc.@var{netname}.pid}. + +@item -o, --option=[@var{HOST}.]@var{KEY}=@var{VALUE} +Without specifying a @var{HOST}, this will set server configuration variable @var{KEY} to @var{VALUE}. +If specified as @var{HOST}.@var{KEY}=@var{VALUE}, +this will set the host configuration variable @var{KEY} of the host named @var{HOST} to @var{VALUE}. +This option can be used more than once to specify multiple configuration variables. + +@item -L, --mlock +Lock tinc into main memory. +This will prevent sensitive data like shared private keys to be written to the system swap files/partitions. + +This option is not supported on all platforms. + +@item --logfile[=@var{file}] +Write log entries to a file instead of to the system logging facility. +If @var{file} is omitted, the default is @file{@value{localstatedir}/log/tinc.@var{netname}.log}. + +@item --bypass-security +Disables encryption and authentication. +Only useful for debugging. + +@item -R, --chroot +Change process root directory to the directory where the config file is +located (@file{@value{sysconfdir}/tinc/@var{netname}/} as determined by +-n/--net option or as given by -c/--config option), for added security. +The chroot is performed after all the initialization is done, after +writing pid files and opening network sockets. + +Note that this option alone does not do any good without -U/--user, below. + +Note also that tinc can't run scripts anymore (such as tinc-down or host-up), +unless it's setup to be runnable inside chroot environment. + +This option is not supported on all platforms. +@item -U, --user=@var{user} +Switch to the given @var{user} after initialization, at the same time as +chroot is performed (see --chroot above). With this option tinc drops +privileges, for added security. + +This option is not supported on all platforms. + +@item --help +Display a short reminder of these runtime options and terminate. + +@item --version +Output version information and exit. + +@end table + +@c ================================================================== +@node Signals +@section Signals + +@cindex signals +You can also send the following signals to a running tincd process: + +@c from the manpage +@table @samp + +@item ALRM +Forces tinc to try to connect to all uplinks immediately. +Usually tinc attempts to do this itself, +but increases the time it waits between the attempts each time it failed, +and if tinc didn't succeed to connect to an uplink the first time after it started, +it defaults to the maximum time of 15 minutes. + +@item HUP +Partially rereads configuration files. +Connections to hosts whose host config file are removed are closed. +New outgoing connections specified in @file{tinc.conf} will be made. +If the --logfile option is used, this will also close and reopen the log file, +useful when log rotation is used. + +@end table + +@c ================================================================== +@node Debug levels +@section Debug levels + +@cindex debug levels +The tinc daemon can send a lot of messages to the syslog. +The higher the debug level, the more messages it will log. +Each level inherits all messages of the previous level: + +@c from the manpage +@table @samp + +@item 0 +This will log a message indicating tinc has started along with a version number. +It will also log any serious error. + +@item 1 +This will log all connections that are made with other tinc daemons. + +@item 2 +This will log status and error messages from scripts and other tinc daemons. + +@item 3 +This will log all requests that are exchanged with other tinc daemons. These include +authentication, key exchange and connection list updates. + +@item 4 +This will log a copy of everything received on the meta socket. + +@item 5 +This will log all network traffic over the virtual private network. + +@end table + +@c ================================================================== +@node Solving problems +@section Solving problems -@item KEY_CHANGED -The source computer wants to tell that it has regenerated its private -and public keys, so anything going there must be encrypted with a new -shared key. +If tinc starts without problems, but if the VPN doesn't work, you will have to find the cause of the problem. +The first thing to do is to start tinc with a high debug level in the foreground, +so you can directly see everything tinc logs: @example +tincd -n @var{netname} -d5 -D +@end example + +If tinc does not log any error messages, then you might want to check the following things: + +@itemize +@item @file{tinc-up} script +Does this script contain the right commands? +Normally you must give the interface the address of this host on the VPN, and the netmask must be big enough so that the entire VPN is covered. + +@item Subnet +Does the Subnet (or Subnets) in the host configuration file of this host match the portion of the VPN that belongs to this host? + +@item Firewalls and NATs +Do you have a firewall or a NAT device (a masquerading firewall or perhaps an ADSL router that performs masquerading)? +If so, check that it allows TCP and UDP traffic on port 655. +If it masquerades and the host running tinc is behind it, make sure that it forwards TCP and UDP traffic to port 655 to the host running tinc. +You can add @samp{TCPOnly = yes} to your host config file to force tinc to only use a single TCP connection, +this works through most firewalls and NATs. + +@end itemize + + +@c ================================================================== +@node Error messages +@section Error messages + +What follows is a list of the most common error messages you might find in the logs. +Some of them will only be visible if the debug level is high enough. + +@table @samp +@item Could not open /dev/tap0: No such device - bytes | Contents ----------------------- - 0 | `162' - 1-4 | The source VPN IP address +@itemize +@item You forgot to `modprobe netlink_dev' or `modprobe ethertap'. +@item You forgot to compile `Netlink device emulation' in the kernel. +@end itemize +@item Can't write to /dev/net/tun: No such device + +@itemize +@item You forgot to `modprobe tun'. +@item You forgot to compile `Universal TUN/TAP driver' in the kernel. +@item The tun device is located somewhere else in @file{/dev/}. +@end itemize + +@item Network address and prefix length do not match! + +@itemize +@item The Subnet field must contain a @emph{network} address, trailing bits should be 0. +@item If you only want to use one IP address, set the netmask to /32. +@end itemize + +@item Error reading RSA key file `rsa_key.priv': No such file or directory + +@itemize +@item You forgot to create a public/private keypair. +@item Specify the complete pathname to the private key file with the @samp{PrivateKeyFile} option. +@end itemize + +@item Warning: insecure file permissions for RSA private key file `rsa_key.priv'! + +@itemize +@item The private key file is readable by users other than root. +Use chmod to correct the file permissions. +@end itemize + +@item Creating metasocket failed: Address family not supported + +@itemize +@item By default tinc tries to create both IPv4 and IPv6 sockets. +On some platforms this might not be implemented. +If the logs show @samp{Ready} later on, then at least one metasocket was created, +and you can ignore this message. +You can add @samp{AddressFamily = ipv4} to @file{tinc.conf} to prevent this from happening. +@end itemize + +@item Cannot route packet: unknown IPv4 destination 1.2.3.4 + +@itemize +@item You try to send traffic to a host on the VPN for which no Subnet is known. +@item If it is a broadcast address (ending in .255), it probably is a samba server or a Windows host sending broadcast packets. +You can ignore it. +@end itemize + +@item Cannot route packet: ARP request for unknown address 1.2.3.4 + +@itemize +@item You try to send traffic to a host on the VPN for which no Subnet is known. +@end itemize + +@item Packet with destination 1.2.3.4 is looping back to us! + +@itemize +@item Something is not configured right. Packets are being sent out to the +virtual network device, but according to the Subnet directives in your host configuration +file, those packets should go to your own host. Most common mistake is that +you have a Subnet line in your host configuration file with a prefix length which is +just as large as the prefix of the virtual network interface. The latter should in almost all +cases be larger. Rethink your configuration. +Note that you will only see this message if you specified a debug +level of 5 or higher! +@item Chances are that a @samp{Subnet = ...} line in the host configuration file of this tinc daemon is wrong. +Change it to a subnet that is accepted locally by another interface, +or if that is not the case, try changing the prefix length into /32. +@end itemize + +@item Node foo (1.2.3.4) is not reachable + +@itemize +@item Node foo does not have a connection anymore, its tinc daemon is not running or its connection to the Internet is broken. +@end itemize + +@item Received UDP packet from unknown source 1.2.3.4 (port 12345) + +@itemize +@item If you see this only sporadically, it is harmless and caused by a node sending packets using an old key. +@item If you see this often and another node is not reachable anymore, then a NAT (masquerading firewall) is changing the source address of UDP packets. +You can add @samp{TCPOnly = yes} to host configuration files to force all VPN traffic to go over a TCP connection. +@end itemize + +@item Got bad/bogus/unauthorized REQUEST from foo (1.2.3.4 port 12345) + +@itemize +@item Node foo does not have the right public/private keypair. +Generate new keypairs and distribute them again. +@item An attacker tries to gain access to your VPN. +@item A network error caused corruption of metadata sent from foo. +@end itemize + +@end table + +@c ================================================================== +@node Sending bug reports +@section Sending bug reports + +If you really can't find the cause of a problem, or if you suspect tinc is not working right, +you can send us a bugreport, see @ref{Contact information}. +Be sure to include the following information in your bugreport: + +@itemize +@item A clear description of what you are trying to achieve and what the problem is. +@item What platform (operating system, version, hardware architecture) and which version of tinc you use. +@item If compiling tinc fails, a copy of @file{config.log} and the error messages you get. +@item Otherwise, a copy of @file{tinc.conf}, @file{tinc-up} and all files in the @file{hosts/} directory. +@item The output of the commands @samp{ifconfig -a} and @samp{route -n} (or @samp{netstat -rn} if that doesn't work). +@item The output of any command that fails to work as it should (like ping or traceroute). +@end itemize + +@c ================================================================== +@node Controlling tinc +@chapter Controlling tinc + +@cindex command line interface +You can start, stop, control and inspect a running tincd through the tinc +command. A quick example: + +@example +tinc -n @var{netname} reload @end example +@cindex shell +If tinc is started without a command, it will act as a shell; it will display a +prompt, and commands can be entered on the prompt. If tinc is compiled with +libreadline, history and command completion are available on the prompt. One +can also pipe a script containing commands through tinc. In that case, lines +starting with a # symbol will be ignored. + +@menu +* tinc runtime options:: +* tinc environment variables:: +* tinc commands:: +* tinc examples:: +* tinc top:: +@end menu + + +@c ================================================================== +@node tinc runtime options +@section tinc runtime options + +@c from the manpage +@table @option +@item -c, --config=@var{path} +Read configuration options from the directory @var{path}. The default is +@file{@value{sysconfdir}/tinc/@var{netname}/}. + +@item -n, --net=@var{netname} +Use configuration for net @var{netname}. @xref{Multiple networks}. + +@item --pidfile=@var{filename} +Use the cookie from @var{filename} to authenticate with a running tinc daemon. +If unspecified, the default is +@file{@value{localstatedir}/run/tinc.@var{netname}.pid}. + +@item --force +Force some commands to work despite warnings. + +@item --help +Display a short reminder of runtime options and commands, then terminate. + +@item --version +Output version information and exit. + +@end table +@c ================================================================== +@node tinc environment variables +@section tinc environment variables + +@table @env +@cindex NETNAME +@item NETNAME +If no netname is specified on the command line with the @option{-n} option, +the value of this environment variable is used. @end table +@c ================================================================== +@node tinc commands +@section tinc commands + +@c from the manpage +@table @code + +@cindex init +@item init [@var{name}] +Create initial configuration files and RSA and Ed25519 keypairs with default length. +If no @var{name} for this node is given, it will be asked for. + +@cindex get +@item get @var{variable} +Print the current value of configuration variable @var{variable}. +If more than one variable with the same name exists, +the value of each of them will be printed on a separate line. + +@cindex set +@item set @var{variable} @var{value} +Set configuration variable @var{variable} to the given @var{value}. +All previously existing configuration variables with the same name are removed. +To set a variable for a specific host, use the notation @var{host}.@var{variable}. + +@cindex add +@item add @var{variable} @var{value} +As above, but without removing any previously existing configuration variables. +If the variable already exists with the given value, nothing happens. + +@cindex del +@item del @var{variable} [@var{value}] +Remove configuration variables with the same name and @var{value}. +If no @var{value} is given, all configuration variables with the same name will be removed. + +@cindex edit +@item edit @var{filename} +Start an editor for the given configuration file. +You do not need to specify the full path to the file. + +@cindex export +@item export +Export the host configuration file of the local node to standard output. + +@cindex export-all +@item export-all +Export all host configuration files to standard output. + +@cindex import +@item import +Import host configuration file(s) generated by the tinc export command from standard input. +Already existing host configuration files are not overwritten unless the option --force is used. + +@cindex exchange +@item exchange +The same as export followed by import. + +@cindex exchange-all +@item exchange-all +The same as export-all followed by import. + +@cindex invite +@item invite @var{name} +Prepares an invitation for a new node with the given @var{name}, +and prints a short invitation URL that can be used with the join command. + +@cindex join +@item join [@var{URL}] +Join an existing VPN using an invitation URL created using the invite command. +If no @var{URL} is given, it will be read from standard input. + +@cindex start +@item start [tincd options] +Start @samp{tincd}, optionally with the given extra options. + +@cindex stop +@item stop +Stop @samp{tincd}. + +@cindex restart +@item restart [tincd options] +Restart @samp{tincd}, optionally with the given extra options. + +@cindex reload +@item reload +Partially rereads configuration files. Connections to hosts whose host +config files are removed are closed. New outgoing connections specified +in @file{tinc.conf} will be made. + +@cindex pid +@item pid +Shows the PID of the currently running @samp{tincd}. + +@cindex generate-keys +@item generate-keys [@var{bits}] +Generate both RSA and Ed25519 keypairs (see below) and exit. +tinc will ask where you want to store the files, but will default to the +configuration directory (you can use the -c or -n option). + +@cindex generate-ed25519-keys +@item generate-ed25519-keys +Generate public/private Ed25519 keypair and exit. + +@cindex generate-rsa-keys +@item generate-rsa-keys [@var{bits}] +Generate public/private RSA keypair and exit. If @var{bits} is omitted, the +default length will be 2048 bits. When saving keys to existing files, tinc +will not delete the old keys; you have to remove them manually. + +@cindex dump +@item dump [reachable] nodes +Dump a list of all known nodes in the VPN. +If the reachable keyword is used, only lists reachable nodes. + +@item dump edges +Dump a list of all known connections in the VPN. + +@item dump subnets +Dump a list of all known subnets in the VPN. + +@item dump connections +Dump a list of all meta connections with ourself. + +@cindex graph +@item dump graph | digraph +Dump a graph of the VPN in dotty format. +Nodes are colored according to their reachability: +red nodes are unreachable, orange nodes are indirectly reachable, green nodes are directly reachable. +Black nodes are either directly or indirectly reachable, but direct reachability has not been tried yet. + +@item dump invitations +Dump a list of outstanding invitations. +The filename of the invitation, as well as the name of the node that is being invited is shown for each invitation. + +@cindex info +@item info @var{node} | @var{subnet} | @var{address} +Show information about a particular @var{node}, @var{subnet} or @var{address}. +If an @var{address} is given, any matching subnet will be shown. + +@cindex purge +@item purge +Purges all information remembered about unreachable nodes. + +@cindex debug +@item debug @var{level} +Sets debug level to @var{level}. + +@cindex log +@item log [@var{level}] +Capture log messages from a running tinc daemon. +An optional debug level can be given that will be applied only for log messages sent to tinc. + +@cindex retry +@item retry +Forces tinc to try to connect to all uplinks immediately. +Usually tinc attempts to do this itself, +but increases the time it waits between the attempts each time it failed, +and if tinc didn't succeed to connect to an uplink the first time after it started, +it defaults to the maximum time of 15 minutes. + +@cindex disconnect +@item disconnect @var{node} +Closes the meta connection with the given @var{node}. + +@cindex top +@item top +If tinc is compiled with libcurses support, this will display live traffic statistics for all the known nodes, +similar to the UNIX top command. +See below for more information. + +@cindex pcap +@item pcap +Dump VPN traffic going through the local tinc node in pcap-savefile format to standard output, +from where it can be redirected to a file or piped through a program that can parse it directly, +such as tcpdump. + +@cindex network +@item network [@var{netname}] +If @var{netname} is given, switch to that network. +Otherwise, display a list of all networks for which configuration files exist. + +@cindex fsck +@item fsck +This will check the configuration files for possible problems, +such as unsafe file permissions, missing executable bit on script, +unknown and obsolete configuration variables, wrong public and/or private keys, and so on. + +When problems are found, this will be printed on a line with WARNING or ERROR in front of it. +Most problems must be corrected by the user itself, however in some cases (like file permissions and missing public keys), +tinc will ask if it should fix the problem. + +@cindex sign +@item sign [@var{filename}] +Sign a file with the local node's private key. +If no @var{filename} is given, the file is read from standard input. +The signed file is written to standard output. + +@cindex verify +@item verify @var{name} [@var{filename}] + +Check the signature of a file against a node's public key. +The @var{name} of the node must be given, +or can be "." to check against the local node's public key, +or "*" to allow a signature from any node whose public key is known. +If no @var{filename} is given, the file is read from standard input. +If the verification is succesful, a copy of the input with the signature removed is written to standard output, and the exit code will be zero. +If the verification failed, nothing will be written to standard output, and the exit code will be non-zero. + +@end table @c ================================================================== -@node About us, Concept Index, Technical information, Top +@node tinc examples +@section tinc examples + +Examples of some commands: + +@example +tinc -n vpn dump graph | circo -Txlib +tinc -n vpn pcap | tcpdump -r - +tinc -n vpn top +@end example + +Examples of changing the configuration using tinc: + +@example +tinc -n vpn init foo +tinc -n vpn add Subnet 192.168.1.0/24 +tinc -n vpn add bar.Address bar.example.com +tinc -n vpn add ConnectTo bar +tinc -n vpn export | gpg --clearsign | mail -s "My config" vpnmaster@@example.com +@end example + +@c ================================================================== +@node tinc top +@section tinc top + +@cindex top +The top command connects to a running tinc daemon and repeatedly queries its per-node traffic counters. +It displays a list of all the known nodes in the left-most column, +and the amount of bytes and packets read from and sent to each node in the other columns. +By default, the information is updated every second. +The behaviour of the top command can be changed using the following keys: + +@table @key + +@item s +Change the interval between updates. +After pressing the @key{s} key, enter the desired interval in seconds, followed by enter. +Fractional seconds are honored. +Intervals lower than 0.1 seconds are not allowed. + +@item c +Toggle between displaying current traffic rates (in packets and bytes per second) +and cummulative traffic (total packets and bytes since the tinc daemon started). + +@item n +Sort the list of nodes by name. + +@item i +Sort the list of nodes by incoming amount of bytes. + +@item I +Sort the list of nodes by incoming amount of packets. + +@item o +Sort the list of nodes by outgoing amount of bytes. + +@item O +Sort the list of nodes by outgoing amount of packets. + +@item t +Sort the list of nodes by sum of incoming and outgoing amount of bytes. + +@item T +Sort the list of nodes by sum of incoming and outgoing amount of packets. + +@item b +Show amount of traffic in bytes. + +@item k +Show amount of traffic in kilobytes. + +@item M +Show amount of traffic in megabytes. + +@item G +Show amount of traffic in gigabytes. + +@item q +Quit. + +@end table + + +@c ================================================================== +@node Technical information +@chapter Technical information + + +@menu +* The connection:: +* The meta-protocol:: +* Security:: +@end menu + + +@c ================================================================== +@node The connection +@section The connection + +@cindex connection +Tinc is a daemon that takes VPN data and transmit that to another host +computer over the existing Internet infrastructure. + +@menu +* The UDP tunnel:: +* The meta-connection:: +@end menu + + +@c ================================================================== +@node The UDP tunnel +@subsection The UDP tunnel + +@cindex virtual network device +@cindex frame type +The data itself is read from a character device file, the so-called +@emph{virtual network device}. This device is associated with a network +interface. Any data sent to this interface can be read from the device, +and any data written to the device gets sent from the interface. +There are two possible types of virtual network devices: +`tun' style, which are point-to-point devices which can only handle IPv4 and/or IPv6 packets, +and `tap' style, which are Ethernet devices and handle complete Ethernet frames. + +So when tinc reads an Ethernet frame from the device, it determines its +type. When tinc is in it's default routing mode, it can handle IPv4 and IPv6 +packets. Depending on the Subnet lines, it will send the packets off to their destination IP address. +In the `switch' and `hub' mode, tinc will use broadcasts and MAC address discovery +to deduce the destination of the packets. +Since the latter modes only depend on the link layer information, +any protocol that runs over Ethernet is supported (for instance IPX and Appletalk). +However, only `tap' style devices provide this information. + +After the destination has been determined, +the packet will be compressed (optionally), +a sequence number will be added to the packet, +the packet will then be encrypted +and a message authentication code will be appended. + +@cindex encapsulating +@cindex UDP +When that is done, time has come to actually transport the +packet to the destination computer. We do this by sending the packet +over an UDP connection to the destination host. This is called +@emph{encapsulating}, the VPN packet (though now encrypted) is +encapsulated in another IP datagram. + +When the destination receives this packet, the same thing happens, only +in reverse. So it checks the message authentication code, decrypts the contents of the UDP datagram, +checks the sequence number +and writes the decrypted information to its own virtual network device. + +If the virtual network device is a `tun' device (a point-to-point tunnel), +there is no problem for the kernel to accept a packet. +However, if it is a `tap' device (this is the only available type on FreeBSD), +the destination MAC address must match that of the virtual network interface. +If tinc is in it's default routing mode, ARP does not work, so the correct destination MAC +can not be known by the sending host. +Tinc solves this by letting the receiving end detect the MAC address of its own virtual network interface +and overwriting the destination MAC address of the received packet. + +In switch or hub modes ARP does work so the sender already knows the correct destination MAC address. +In those modes every interface should have a unique MAC address, so make sure they are not the same. +Because switch and hub modes rely on MAC addresses to function correctly, +these modes cannot be used on the following operating systems which don't have a `tap' style virtual network device: +OpenBSD, NetBSD, Darwin and Solaris. + + +@c ================================================================== +@node The meta-connection +@subsection The meta-connection + +Having only a UDP connection available is not enough. Though suitable +for transmitting data, we want to be able to reliably send other +information, such as routing and session key information to somebody. + +@cindex TCP +TCP is a better alternative, because it already contains protection +against information being lost, unlike UDP. + +So we establish two connections. One for the encrypted VPN data, and one +for other information, the meta-data. Hence, we call the second +connection the meta-connection. We can now be sure that the +meta-information doesn't get lost on the way to another computer. + +@cindex data-protocol +@cindex meta-protocol +Like with any communication, we must have a protocol, so that everybody +knows what everything stands for, and how she should react. Because we +have two connections, we also have two protocols. The protocol used for +the UDP data is the ``data-protocol,'' the other one is the +``meta-protocol.'' + +The reason we don't use TCP for both protocols is that UDP is much +better for encapsulation, even while it is less reliable. The real +problem is that when TCP would be used to encapsulate a TCP stream +that's on the private network, for every packet sent there would be +three ACKs sent instead of just one. Furthermore, if there would be +a timeout, both TCP streams would sense the timeout, and both would +start re-sending packets. + + +@c ================================================================== +@node The meta-protocol +@section The meta-protocol + +The meta protocol is used to tie all tinc daemons together, and +exchange information about which tinc daemon serves which virtual +subnet. + +The meta protocol consists of requests that can be sent to the other +side. Each request has a unique number and several parameters. All +requests are represented in the standard ASCII character set. It is +possible to use tools such as telnet or netcat to connect to a tinc +daemon started with the --bypass-security option +and to read and write requests by hand, provided that one +understands the numeric codes sent. + +The authentication scheme is described in @ref{Security}. After a +successful authentication, the server and the client will exchange all the +information about other tinc daemons and subnets they know of, so that both +sides (and all the other tinc daemons behind them) have their information +synchronised. + +@cindex ADD_EDGE +@cindex ADD_SUBNET +@example +message +------------------------------------------------------------------ +ADD_EDGE node1 node2 21.32.43.54 655 222 0 + | | | | | +-> options + | | | | +----> weight + | | | +--------> UDP port of node2 + | | +----------------> real address of node2 + | +-------------------------> name of destination node + +-------------------------------> name of source node + +ADD_SUBNET node 192.168.1.0/24 + | | +--> prefixlength + | +--------> network address + +------------------> owner of this subnet +------------------------------------------------------------------ +@end example + +The ADD_EDGE messages are to inform other tinc daemons that a connection between +two nodes exist. The address of the destination node is available so that +VPN packets can be sent directly to that node. + +The ADD_SUBNET messages inform other tinc daemons that certain subnets belong +to certain nodes. tinc will use it to determine to which node a VPN packet has +to be sent. + +@cindex DEL_EDGE +@cindex DEL_SUBNET +@example +message +------------------------------------------------------------------ +DEL_EDGE node1 node2 + | +----> name of destination node + +----------> name of source node + +DEL_SUBNET node 192.168.1.0/24 + | | +--> prefixlength + | +--------> network address + +------------------> owner of this subnet +------------------------------------------------------------------ +@end example + +In case a connection between two daemons is closed or broken, DEL_EDGE messages +are sent to inform the other daemons of that fact. Each daemon will calculate a +new route to the the daemons, or mark them unreachable if there isn't any. + +@cindex REQ_KEY +@cindex ANS_KEY +@cindex KEY_CHANGED +@example +message +------------------------------------------------------------------ +REQ_KEY origin destination + | +--> name of the tinc daemon it wants the key from + +----------> name of the daemon that wants the key + +ANS_KEY origin destination 4ae0b0a82d6e0078 91 64 4 + | | \______________/ | | +--> MAC length + | | | | +-----> digest algorithm + | | | +--------> cipher algorithm + | | +--> 128 bits key + | +--> name of the daemon that wants the key + +----------> name of the daemon that uses this key + +KEY_CHANGED origin + +--> daemon that has changed it's packet key +------------------------------------------------------------------ +@end example + +The keys used to encrypt VPN packets are not sent out directly. This is +because it would generate a lot of traffic on VPNs with many daemons, and +chances are that not every tinc daemon will ever send a packet to every +other daemon. Instead, if a daemon needs a key it sends a request for it +via the meta connection of the nearest hop in the direction of the +destination. + +@cindex PING +@cindex PONG +@example +daemon message +------------------------------------------------------------------ +origin PING +dest. PONG +------------------------------------------------------------------ +@end example + +There is also a mechanism to check if hosts are still alive. Since network +failures or a crash can cause a daemon to be killed without properly +shutting down the TCP connection, this is necessary to keep an up to date +connection list. PINGs are sent at regular intervals, except when there +is also some other traffic. A little bit of salt (random data) is added +with each PING and PONG message, to make sure that long sequences of PING/PONG +messages without any other traffic won't result in known plaintext. + +This basically covers what is sent over the meta connection by tinc. + + +@c ================================================================== +@node Security +@section Security + +@cindex TINC +@cindex Cabal +Tinc got its name from ``TINC,'' short for @emph{There Is No Cabal}; the +alleged Cabal was/is an organisation that was said to keep an eye on the +entire Internet. As this is exactly what you @emph{don't} want, we named +the tinc project after TINC. + +@cindex SVPN +But in order to be ``immune'' to eavesdropping, you'll have to encrypt +your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does +exactly that: encrypt. +However, encryption in itself does not prevent an attacker from modifying the encrypted data. +Therefore, tinc also authenticates the data. +Finally, tinc uses sequence numbers (which themselves are also authenticated) to prevent an attacker from replaying valid packets. + +Since version 1.1pre3, tinc has two protocols used to protect your data; the legacy protocol, and the new Simple Peer-to-Peer Security (SPTPS) protocol. +The SPTPS protocol is designed to address some weaknesses in the legacy protocol. +The new authentication protocol is used when two nodes connect to each other that both have the ExperimentalProtocol option set to yes, +otherwise the legacy protocol will be used. + +@menu +* Legacy authentication protocol:: +* Simple Peer-to-Peer Security:: +* Encryption of network packets:: +* Security issues:: +@end menu + + +@c ================================================================== +@node Legacy authentication protocol +@subsection Legacy authentication protocol + +@cindex legacy authentication protocol + +@cindex ID +@cindex META_KEY +@cindex CHALLENGE +@cindex CHAL_REPLY +@cindex ACK +@example +daemon message +-------------------------------------------------------------------------- +client + +server + +client ID client 17.2 + | | +-> minor protocol version + | +----> major protocol version + +--------> name of tinc daemon + +server ID server 17.2 + | | +-> minor protocol version + | +----> major protocol version + +--------> name of tinc daemon + +client META_KEY 94 64 0 0 5f0823a93e35b69e...7086ec7866ce582b + | | | | \_________________________________/ + | | | | +-> RSAKEYLEN bits totally random string S1, + | | | | encrypted with server's public RSA key + | | | +-> compression level + | | +---> MAC length + | +------> digest algorithm NID + +---------> cipher algorithm NID + +server META_KEY 94 64 0 0 6ab9c1640388f8f0...45d1a07f8a672630 + | | | | \_________________________________/ + | | | | +-> RSAKEYLEN bits totally random string S2, + | | | | encrypted with client's public RSA key + | | | +-> compression level + | | +---> MAC length + | +------> digest algorithm NID + +---------> cipher algorithm NID +-------------------------------------------------------------------------- +@end example + +The protocol allows each side to specify encryption algorithms and parameters, +but in practice they are always fixed, since older versions of tinc did not +allow them to be different from the default values. The cipher is always +Blowfish in OFB mode, the digest is SHA1, but the MAC length is zero and no +compression is used. + +From now on: +@itemize +@item the client will symmetrically encrypt outgoing traffic using S1 +@item the server will symmetrically encrypt outgoing traffic using S2 +@end itemize + +@example +-------------------------------------------------------------------------- +client CHALLENGE da02add1817c1920989ba6ae2a49cecbda0 + \_________________________________/ + +-> CHALLEN bits totally random string H1 + +server CHALLENGE 57fb4b2ccd70d6bb35a64c142f47e61d57f + \_________________________________/ + +-> CHALLEN bits totally random string H2 + +client CHAL_REPLY 816a86 + +-> 160 bits SHA1 of H2 + +server CHAL_REPLY 928ffe + +-> 160 bits SHA1 of H1 + +After the correct challenge replies are received, both ends have proved +their identity. Further information is exchanged. + +client ACK 655 123 0 + | | +-> options + | +----> estimated weight + +--------> listening port of client + +server ACK 655 321 0 + | | +-> options + | +----> estimated weight + +--------> listening port of server +-------------------------------------------------------------------------- +@end example + +This legacy authentication protocol has several weaknesses, pointed out by security export Peter Gutmann. +First, data is encrypted with RSA without padding. +Padding schemes are designed to prevent attacks when the size of the plaintext is not equal to the size of the RSA key. +Tinc always encrypts random nonces that have the same size as the RSA key, so we do not believe this leads to a break of the security. +There might be timing or other side-channel attacks against RSA encryption and decryption, tinc does not employ any protection against those. +Furthermore, both sides send identical messages to each other, there is no distinction between server and client, +which could make a MITM attack easier. +However, no exploit is known in which a third party who is not already trusted by other nodes in the VPN could gain access. +Finally, the RSA keys are used to directly encrypt the session keys, which means that if the RSA keys are compromised, it is possible to decrypt all previous VPN traffic. +In other words, the legacy protocol does not provide perfect forward secrecy. + +@c ================================================================== +@node Simple Peer-to-Peer Security +@subsection Simple Peer-to-Peer Security +@cindex SPTPS + +The SPTPS protocol is designed to address the weaknesses in the legacy protocol. +SPTPS is based on TLS 1.2, but has been simplified: there is no support for exchanging public keys, and there is no cipher suite negotiation. +Instead, SPTPS always uses a very strong cipher suite: +peers authenticate each other using 521 bits ECC keys, +Diffie-Hellman using ephemeral 521 bits ECC keys is used to provide perfect forward secrecy (PFS), +AES-256-CTR is used for encryption, and HMAC-SHA-256 for message authentication. + +Similar to TLS, messages are split up in records. +A complete logical record contains the following information: + +@itemize +@item uint32_t seqno (network byte order) +@item uint16_t length (network byte order) +@item uint8_t type +@item opaque data[length] +@item opaque hmac[HMAC_SIZE] (HMAC over all preceding fields) +@end itemize + +Depending on whether SPTPS records are sent via TCP or UDP, either the seqno or the length field is omitted on the wire +(but they are still included in the calculation of the HMAC); +for TCP packets are guaranteed to arrive in-order so we can infer the seqno, but packets can be split or merged, so we still need the length field to determine the boundaries between records; +for UDP packets we know that there is exactly one record per packet, and we know the length of a packet, but packets can be dropped, duplicated and/or reordered, so we need to include the seqno. + +The type field is used to distinguish between application records or handshake records. +Types 0 to 127 are application records, type 128 is a handshake record, and types 129 to 255 are reserved. + +Before the initial handshake, no fields are encrypted, and the HMAC field is not present. +After the authentication handshake, the length (if present), type and data fields are encrypted, and the HMAC field is present. +For UDP packets, the seqno field is not encrypted, as it is used to determine the value of the counter used for encryption. + +The authentication consists of an exchange of Key EXchange, SIGnature and ACKnowledge messages, transmitted using type 128 records. + +Overview: + +@example +Initiator Responder +--------------------- +KEX -> + <- KEX +SIG -> + <- SIG + +...encrypt and HMAC using session keys from now on... + +App -> + <- App +... + ... + +...key renegotiation starts here... + +KEX -> + <- KEX +SIG -> + <- SIG +ACK -> + <- ACK + +...encrypt and HMAC using new session keys from now on... + +App -> + <- App +... + ... +--------------------- +@end example + +Note that the responder does not need to wait before it receives the first KEX message, +it can immediately send its own once it has accepted an incoming connection. + +Key EXchange message: + +@itemize +@item uint8_t kex_version (always 0 in this version of SPTPS) +@item opaque nonce[32] (random number) +@item opaque ecdh_key[ECDH_SIZE] +@end itemize + +SIGnature message: + +@itemize +@item opaque ecdsa_signature[ECDSA_SIZE] +@end itemize + +ACKnowledge message: + +@itemize +@item empty (only sent after key renegotiation) +@end itemize + +Remarks: + +@itemize +@item At the start, both peers generate a random nonce and an Elliptic Curve public key and send it to the other in the KEX message. +@item After receiving the other's KEX message, both KEX messages are concatenated (see below), + and the result is signed using ECDSA. + The result is sent to the other. +@item After receiving the other's SIG message, the signature is verified. + If it is correct, the shared secret is calculated from the public keys exchanged in the KEX message using the Elliptic Curve Diffie-Helman algorithm. +@item The shared secret key is expanded using a PRF. + Both nonces and the application specific label are also used as input for the PRF. +@item An ACK message is sent only when doing key renegotiation, and is sent using the old encryption keys. +@item The expanded key is used to key the encryption and HMAC algorithms. +@end itemize + +The signature is calculated over this string: + +@itemize +@item uint8_t initiator (0 = local peer, 1 = remote peer is initiator) +@item opaque remote_kex_message[1 + 32 + ECDH_SIZE] +@item opaque local_kex_message[1 + 32 + ECDH_SIZE] +@item opaque label[label_length] +@end itemize + +The PRF is calculated as follows: + +@itemize +@item A HMAC using SHA512 is used, the shared secret is used as the key. +@item For each block of 64 bytes, a HMAC is calculated. For block n: hmac[n] = + HMAC_SHA512(hmac[n - 1] + seed) +@item For the first block (n = 1), hmac[0] is given by HMAC_SHA512(zeroes + seed), + where zeroes is a block of 64 zero bytes. +@end itemize + +The seed is as follows: + +@itemize +@item const char[13] "key expansion" +@item opaque responder_nonce[32] +@item opaque initiator_nonce[32] +@item opaque label[label_length] +@end itemize + +The expanded key is used as follows: + +@itemize +@item opaque responder_cipher_key[CIPHER_KEYSIZE] +@item opaque responder_digest_key[DIGEST_KEYSIZE] +@item opaque initiator_cipher_key[CIPHER_KEYSIZE] +@item opaque initiator_digest_key[DIGEST_KEYSIZE] +@end itemize + +Where initiator_cipher_key is the key used by session initiator to encrypt +messages sent to the responder. + +When using 256 bits Ed25519 keys, the AES-256-CTR cipher and HMAC-SHA-256 digest algorithm, +the sizes are as follows: + +@example +ECDH_SIZE: 32 (= 256/8) +ECDSA_SIZE: 64 (= 2 * 256/8) +CIPHER_KEYSIZE: 48 (= 256/8 + 128/8) +DIGEST_KEYSIZE: 32 (= 256/8) +@end example + +Note that the cipher key also includes the initial value for the counter. + +@c ================================================================== +@node Encryption of network packets +@subsection Encryption of network packets +@cindex encryption + +A data packet can only be sent if the encryption key is known to both +parties, and the connection is activated. If the encryption key is not +known, a request is sent to the destination using the meta connection +to retrieve it. + +@cindex UDP +The UDP packets can be either encrypted with the legacy protocol or with SPTPS. +In case of the legacy protocol, the UDP packet containing the network packet from the VPN has the following layout: + +@example +... | IP header | UDP header | seqno | VPN packet | MAC | UDP trailer + \___________________/\_____/ + | | + V +---> digest algorithm + Encrypted with symmetric cipher +@end example + + + + +So, the entire VPN packet is encrypted using a symmetric cipher, including a 32 bits +sequence number that is added in front of the actual VPN packet, to act as a unique +IV for each packet and to prevent replay attacks. A message authentication code +is added to the UDP packet to prevent alteration of packets. +Tinc by default encrypts network packets using Blowfish with 128 bit keys in CBC mode +and uses 4 byte long message authentication codes to make sure +eavesdroppers cannot get and cannot change any information at all from the +packets they can intercept. The encryption algorithm and message authentication +algorithm can be changed in the configuration. The length of the message +authentication codes is also adjustable. The length of the key for the +encryption algorithm is always the default length used by LibreSSL/OpenSSL. + +The SPTPS protocol is described in @ref{Simple Peer-to-Peer Security}. +For comparison, this is how SPTPS UDP packets look: + +@example +... | IP header | UDP header | seqno | type | VPN packet | MAC | UDP trailer + \__________________/\_____/ + | | + V +---> digest algorithm + Encrypted with symmetric cipher +@end example + +The difference is that the seqno is not encrypted, since the encryption cipher is used in CTR mode, +and therefore the seqno must be known before the packet can be decrypted. +Furthermore, the MAC is never truncated. +The SPTPS protocol always uses the AES-256-CTR cipher and HMAC-SHA-256 digest, +this cannot be changed. + + +@c ================================================================== +@node Security issues +@subsection Security issues + +In August 2000, we discovered the existence of a security hole in all versions +of tinc up to and including 1.0pre2. This had to do with the way we exchanged +keys. Since then, we have been working on a new authentication scheme to make +tinc as secure as possible. The current version uses the LibreSSL or OpenSSL library and +uses strong authentication with RSA keys. + +On the 29th of December 2001, Jerome Etienne posted a security analysis of tinc +1.0pre4. Due to a lack of sequence numbers and a message authentication code +for each packet, an attacker could possibly disrupt certain network services or +launch a denial of service attack by replaying intercepted packets. The current +version adds sequence numbers and message authentication codes to prevent such +attacks. + +On the 15th of September 2003, Peter Gutmann posted a security analysis of tinc +1.0.1. He argues that the 32 bit sequence number used by tinc is not a good IV, +that tinc's default length of 4 bytes for the MAC is too short, and he doesn't +like tinc's use of RSA during authentication. We do not know of a security hole +in the legacy protocol of tinc, but it is not as strong as TLS or IPsec. + +This version of tinc comes with an improved protocol, called Simple Peer-to-Peer Security, +which aims to be as strong as TLS with one of the strongest cipher suites. + +Cryptography is a hard thing to get right. We cannot make any +guarantees. Time, review and feedback are the only things that can +prove the security of any cryptographic product. If you wish to review +tinc or give us feedback, you are stronly encouraged to do so. + + +@c ================================================================== +@node Platform specific information +@chapter Platform specific information + +@menu +* Interface configuration:: +* Routes:: +@end menu + +@c ================================================================== +@node Interface configuration +@section Interface configuration + +When configuring an interface, one normally assigns it an address and a +netmask. The address uniquely identifies the host on the network attached to +the interface. The netmask, combined with the address, forms a subnet. It is +used to add a route to the routing table instructing the kernel to send all +packets which fall into that subnet to that interface. Because all packets for +the entire VPN should go to the virtual network interface used by tinc, the +netmask should be such that it encompasses the entire VPN. + +For IPv4 addresses: + +@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface} +@item Linux +@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask} +@item Linux iproute2 +@tab @code{ip addr add} @var{address}@code{/}@var{prefixlength} @code{dev} @var{interface} +@item FreeBSD +@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask} +@item OpenBSD +@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask} +@item NetBSD +@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask} +@item Solaris +@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask} +@item Darwin (MacOS/X) +@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask} +@item Windows +@tab @code{netsh interface ip set address} @var{interface} @code{static} @var{address} @var{netmask} +@end multitable + +For IPv6 addresses: + +@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface} +@item Linux +@tab @code{ifconfig} @var{interface} @code{add} @var{address}@code{/}@var{prefixlength} +@item FreeBSD +@tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength} +@item OpenBSD +@tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength} +@item NetBSD +@tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength} +@item Solaris +@tab @code{ifconfig} @var{interface} @code{inet6 plumb up} +@item +@tab @code{ifconfig} @var{interface} @code{inet6 addif} @var{address} @var{address} +@item Darwin (MacOS/X) +@tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength} +@item Windows +@tab @code{netsh interface ipv6 add address} @var{interface} @code{static} @var{address}/@var{prefixlength} +@end multitable + +On some platforms, when running tinc in switch mode, the VPN interface must be set to tap mode with an ifconfig command: + +@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface} +@item OpenBSD +@tab @code{ifconfig} @var{interface} @code{link0} +@end multitable + +On Linux, it is possible to create a persistent tun/tap interface which will +continue to exist even if tinc quit, although this is normally not required. +It can be useful to set up a tun/tap interface owned by a non-root user, so +tinc can be started without needing any root privileges at all. + +@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface} +@item Linux +@tab @code{ip tuntap add dev} @var{interface} @code{mode} @var{tun|tap} @code{user} @var{username} +@end multitable + +@c ================================================================== +@node Routes +@section Routes + +In some cases it might be necessary to add more routes to the virtual network +interface. There are two ways to indicate which interface a packet should go +to, one is to use the name of the interface itself, another way is to specify +the (local) address that is assigned to that interface (@var{local_address}). The +former way is unambiguous and therefore preferable, but not all platforms +support this. + +Adding routes to IPv4 subnets: + +@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface} +@item Linux +@tab @code{route add -net} @var{network_address} @code{netmask} @var{netmask} @var{interface} +@item Linux iproute2 +@tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface} +@item FreeBSD +@tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} +@item OpenBSD +@tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} +@item NetBSD +@tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} +@item Solaris +@tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface} +@item Darwin (MacOS/X) +@tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} +@item Windows +@tab @code{netsh routing ip add persistentroute} @var{network_address} @var{netmask} @var{interface} @var{local_address} +@end multitable + +Adding routes to IPv6 subnets: + +@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface} +@item Linux +@tab @code{route add -A inet6} @var{network_address}@code{/}@var{prefixlength} @var{interface} +@item Linux iproute2 +@tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface} +@item FreeBSD +@tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address} +@item OpenBSD +@tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength} +@item NetBSD +@tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength} +@item Solaris +@tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface} +@item Darwin (MacOS/X) +@tab ? +@item Windows +@tab @code{netsh interface ipv6 add route} @var{network address}/@var{prefixlength} @var{interface} +@end multitable + + +@c ================================================================== +@node About us @chapter About us @menu -* Contact Information:: -* Authors:: +* Contact information:: +* Authors:: @end menu @c ================================================================== -@node Contact Information, Authors, About us, About us +@node Contact information @section Contact information -tinc's main page is at @url{http://tinc.nl.linux.org/}, +@cindex website +Tinc's website is at @url{https://www.tinc-vpn.org/}, this server is located in the Netherlands. -We have an IRC channel on the Open Projects IRC network. Connect to -@uref{http://openprojects.nu/services/irc.html, irc.openprojects.net}, +@cindex IRC +We have an IRC channel on the FreeNode and OFTC IRC networks. Connect to +@uref{https://freenode.net/, irc.freenode.net} +or +@uref{https://www.oftc.net/, irc.oftc.net} and join channel #tinc. @c ================================================================== -@node Authors, , Contact Information, About us +@node Authors @section Authors @table @asis -@item Ivo Timmermans (zarq) (@email{itimmermans@@bigfoot.com}) -Main coder/hacker and maintainer of the package. - -@item Guus Sliepen (guus) -Originator of it all, co-author. - -@item Wessel Dankers (Ubiq) -General obfuscater of the code. - +@item Ivo Timmermans (zarq) +@item Guus Sliepen (guus) (@email{guus@@tinc-vpn.org}) @end table -Thank you's to: Dekan, Emphyrio, vDong - -Greetings to: braque, Fluor, giggles, macro, smoke, tribbel +We have received a lot of valuable input from users. With their help, +tinc has become the flexible and robust tool that it is today. We have +composed a list of contributions, in the file called @file{THANKS} in +the source distribution. @c ================================================================== -@node Concept Index, , About us, Top -@c node-name, next, previous, up +@node Concept Index @unnumbered Concept Index @c ================================================================== @@ -1178,4 +3409,3 @@ Greetings to: braque, Fluor, giggles, macro, smoke, tribbel @c ================================================================== @contents @bye -