1 \input texinfo @c -*-texinfo-*-
9 @include tincinclude.texi
12 @dircategory Networking tools
14 * tinc: (tinc). The tinc Manual.
17 This is the info manual for @value{PACKAGE} version @value{VERSION}, a Virtual Private Network daemon.
19 Copyright @copyright{} 1998-2009 Ivo Timmermans,
20 Guus Sliepen <guus@@tinc-vpn.org> and
21 Wessel Dankers <wsl@@tinc-vpn.org>.
25 Permission is granted to make and distribute verbatim copies of this
26 manual provided the copyright notice and this permission notice are
27 preserved on all copies.
29 Permission is granted to copy and distribute modified versions of this
30 manual under the conditions for verbatim copying, provided that the
31 entire resulting derived work is distributed under the terms of a
32 permission notice identical to this one.
38 @subtitle Setting up a Virtual Private Network with tinc
39 @author Ivo Timmermans and Guus Sliepen
42 @vskip 0pt plus 1filll
44 This is the info manual for @value{PACKAGE} version @value{VERSION}, a Virtual Private Network daemon.
46 Copyright @copyright{} 1998-2009 Ivo Timmermans,
47 Guus Sliepen <guus@@tinc-vpn.org> and
48 Wessel Dankers <wsl@@tinc-vpn.org>.
52 Permission is granted to make and distribute verbatim copies of this
53 manual provided the copyright notice and this permission notice are
54 preserved on all copies.
56 Permission is granted to copy and distribute modified versions of this
57 manual under the conditions for verbatim copying, provided that the
58 entire resulting derived work is distributed under the terms of a
59 permission notice identical to this one.
64 @c ==================================================================
75 * Technical information::
76 * Platform specific information::
78 * Concept Index:: All used terms explained
82 @c ==================================================================
87 Tinc is a Virtual Private Network (VPN) daemon that uses tunneling and
88 encryption to create a secure private network between hosts on the
91 Because the tunnel appears to the IP level network code as a normal
92 network device, there is no need to adapt any existing software.
93 The encrypted tunnels allows VPN sites to share information with each other
94 over the Internet without exposing any information to others.
96 This document is the manual for tinc. Included are chapters on how to
97 configure your computer to use tinc, as well as the configuration
98 process of tinc itself.
101 * Virtual Private Networks::
103 * Supported platforms::
106 @c ==================================================================
107 @node Virtual Private Networks
108 @section Virtual Private Networks
111 A Virtual Private Network or VPN is a network that can only be accessed
112 by a few elected computers that participate. This goal is achievable in
113 more than just one way.
116 Private networks can consist of a single stand-alone Ethernet LAN. Or
117 even two computers hooked up using a null-modem cable. In these cases,
119 obvious that the network is @emph{private}, no one can access it from the
120 outside. But if your computers are linked to the Internet, the network
121 is not private anymore, unless one uses firewalls to block all private
122 traffic. But then, there is no way to send private data to trusted
123 computers on the other end of the Internet.
126 This problem can be solved by using @emph{virtual} networks. Virtual
127 networks can live on top of other networks, but they use encapsulation to
128 keep using their private address space so they do not interfere with
129 the Internet. Mostly, virtual networks appear like a singe LAN, even though
130 they can span the entire world. But virtual networks can't be secured
131 by using firewalls, because the traffic that flows through it has to go
132 through the Internet, where other people can look at it.
134 As is the case with either type of VPN, anybody could eavesdrop. Or
135 worse, alter data. Hence it's probably advisable to encrypt the data
136 that flows over the network.
138 When one introduces encryption, we can form a true VPN. Other people may
139 see encrypted traffic, but if they don't know how to decipher it (they
140 need to know the key for that), they cannot read the information that flows
141 through the VPN. This is what tinc was made for.
144 @c ==================================================================
149 I really don't quite remember what got us started, but it must have been
150 Guus' idea. He wrote a simple implementation (about 50 lines of C) that
151 used the ethertap device that Linux knows of since somewhere
152 about kernel 2.1.60. It didn't work immediately and he improved it a
153 bit. At this stage, the project was still simply called "vpnd".
155 Since then, a lot has changed---to say the least.
158 Tinc now supports encryption, it consists of a single daemon (tincd) for
159 both the receiving and sending end, it has become largely
160 runtime-configurable---in short, it has become a full-fledged
161 professional package.
163 @cindex traditional VPNs
165 Tinc also allows more than two sites to connect to eachother and form a single VPN.
166 Traditionally VPNs are created by making tunnels, which only have two endpoints.
167 Larger VPNs with more sites are created by adding more tunnels.
168 Tinc takes another approach: only endpoints are specified,
169 the software itself will take care of creating the tunnels.
170 This allows for easier configuration and improved scalability.
172 A lot can---and will be---changed. We have a number of things that we would like to
173 see in the future releases of tinc. Not everything will be available in
174 the near future. Our first objective is to make tinc work perfectly as
175 it stands, and then add more advanced features.
177 Meanwhile, we're always open-minded towards new ideas. And we're
181 @c ==================================================================
182 @node Supported platforms
183 @section Supported platforms
186 Tinc has been verified to work under Linux, FreeBSD, OpenBSD, NetBSD, MacOS/X (Darwin), Solaris, and Windows (both natively and in a Cygwin environment),
187 with various hardware architectures. These are some of the platforms
188 that are supported by the universal tun/tap device driver or other virtual network device drivers.
189 Without such a driver, tinc will most
190 likely compile and run, but it will not be able to send or receive data
194 For an up to date list of supported platforms, please check the list on
196 @uref{http://www.tinc-vpn.org/platforms}.
204 @c Preparing your system
211 @c ==================================================================
213 @chapter Preparations
215 This chapter contains information on how to prepare your system to
219 * Configuring the kernel::
224 @c ==================================================================
225 @node Configuring the kernel
226 @section Configuring the kernel
229 * Configuration of Linux kernels::
230 * Configuration of FreeBSD kernels::
231 * Configuration of OpenBSD kernels::
232 * Configuration of NetBSD kernels::
233 * Configuration of Solaris kernels::
234 * Configuration of Darwin (MacOS/X) kernels::
235 * Configuration of Windows::
239 @c ==================================================================
240 @node Configuration of Linux kernels
241 @subsection Configuration of Linux kernels
243 @cindex Universal tun/tap
244 For tinc to work, you need a kernel that supports the Universal tun/tap device.
245 Most distributions come with kernels that already support this.
246 Here are the options you have to turn on when configuring a new kernel:
249 Code maturity level options
250 [*] Prompt for development and/or incomplete code/drivers
251 Network device support
252 <M> Universal tun/tap device driver support
255 It's not necessary to compile this driver as a module, even if you are going to
256 run more than one instance of tinc.
258 If you decide to build the tun/tap driver as a kernel module, add these lines
259 to @file{/etc/modules.conf}:
262 alias char-major-10-200 tun
266 @c ==================================================================
267 @node Configuration of FreeBSD kernels
268 @subsection Configuration of FreeBSD kernels
270 For FreeBSD version 4.1 and higher, tun and tap drivers are included in the default kernel configuration.
271 Using tap devices is recommended.
274 @c ==================================================================
275 @node Configuration of OpenBSD kernels
276 @subsection Configuration of OpenBSD kernels
278 For OpenBSD version 2.9 and higher,
279 the tun driver is included in the default kernel configuration.
280 There is also a kernel patch from @uref{http://diehard.n-r-g.com/stuff/openbsd/}
281 which adds a tap device to OpenBSD which should work with tinc,
282 but with recent versions of OpenBSD,
283 a tun device can act as a tap device by setting the link0 option with ifconfig.
285 @c ==================================================================
286 @node Configuration of NetBSD kernels
287 @subsection Configuration of NetBSD kernels
289 For NetBSD version 1.5.2 and higher,
290 the tun driver is included in the default kernel configuration.
292 Tunneling IPv6 may not work on NetBSD's tun device.
295 @c ==================================================================
296 @node Configuration of Solaris kernels
297 @subsection Configuration of Solaris kernels
299 For Solaris 8 (SunOS 5.8) and higher,
300 the tun driver may or may not be included in the default kernel configuration.
301 If it isn't, the source can be downloaded from @uref{http://vtun.sourceforge.net/tun/}.
302 For x86 and sparc64 architectures, precompiled versions can be found at @uref{http://www.monkey.org/~dugsong/fragroute/}.
303 If the @file{net/if_tun.h} header file is missing, install it from the source package.
306 @c ==================================================================
307 @node Configuration of Darwin (MacOS/X) kernels
308 @subsection Configuration of Darwin (MacOS/X) kernels
310 Tinc on Darwin relies on a tunnel driver for its data acquisition from the kernel.
311 Tinc supports either the driver from @uref{http://www-user.rhrk.uni-kl.de/~nissler/tuntap/},
312 which supports both tun and tap style devices,
313 and also the driver from from @uref{http://chrisp.de/en/projects/tunnel.html}.
314 The former driver is recommended.
315 The tunnel driver must be loaded before starting tinc with the following command:
322 @c ==================================================================
323 @node Configuration of Windows
324 @subsection Configuration of Windows
326 You will need to install the latest TAP-Win32 driver from OpenVPN.
327 You can download it from @uref{http://openvpn.sourceforge.net}.
328 Using the Network Connections control panel,
329 configure the TAP-Win32 network interface in the same way as you would do from the tinc-up script,
330 as explained in the rest of the documentation.
333 @c ==================================================================
339 Before you can configure or build tinc, you need to have the OpenSSL,
340 zlib and lzo libraries installed on your system. If you try to configure tinc without
341 having them installed, configure will give you an error message, and stop.
351 @c ==================================================================
356 For all cryptography-related functions, tinc uses the functions provided
357 by the OpenSSL library.
359 If this library is not installed, you wil get an error when configuring
360 tinc for build. Support for running tinc without having OpenSSL
361 installed @emph{may} be added in the future.
363 You can use your operating system's package manager to install this if
364 available. Make sure you install the development AND runtime versions
367 If you have to install OpenSSL manually, you can get the source code
368 from @url{http://www.openssl.org/}. Instructions on how to configure,
369 build and install this package are included within the package. Please
370 make sure you build development and runtime libraries (which is the
373 If you installed the OpenSSL libraries from source, it may be necessary
374 to let configure know where they are, by passing configure one of the
375 --with-openssl-* parameters.
378 --with-openssl=DIR OpenSSL library and headers prefix
379 --with-openssl-include=DIR OpenSSL headers directory
380 (Default is OPENSSL_DIR/include)
381 --with-openssl-lib=DIR OpenSSL library directory
382 (Default is OPENSSL_DIR/lib)
386 @subsubheading License
389 The complete source code of tinc is covered by the GNU GPL version 2.
390 Since the license under which OpenSSL is distributed is not directly
391 compatible with the terms of the GNU GPL
392 @uref{http://www.openssl.org/support/faq.html#LEGAL2}, we
393 include an exemption to the GPL (see also the file COPYING.README) to allow
394 everyone to create a statically or dynamically linked executable:
397 This program is released under the GPL with the additional exemption
398 that compiling, linking, and/or using OpenSSL is allowed. You may
399 provide binary packages linked to the OpenSSL libraries, provided that
400 all other requirements of the GPL are met.
403 Since the LZO library used by tinc is also covered by the GPL,
404 we also present the following exemption:
407 Hereby I grant a special exception to the tinc VPN project
408 (http://www.tinc-vpn.org/) to link the LZO library with the OpenSSL library
409 (http://www.openssl.org).
411 Markus F.X.J. Oberhumer
415 @c ==================================================================
420 For the optional compression of UDP packets, tinc uses the functions provided
423 If this library is not installed, you wil get an error when configuring
424 tinc for build. Support for running tinc without having zlib
425 installed @emph{may} be added in the future.
427 You can use your operating system's package manager to install this if
428 available. Make sure you install the development AND runtime versions
431 If you have to install zlib manually, you can get the source code
432 from @url{http://www.gzip.org/zlib/}. Instructions on how to configure,
433 build and install this package are included within the package. Please
434 make sure you build development and runtime libraries (which is the
438 @c ==================================================================
443 Another form of compression is offered using the lzo library.
445 If this library is not installed, you wil get an error when configuring
446 tinc for build. Support for running tinc without having lzo
447 installed @emph{may} be added in the future.
449 You can use your operating system's package manager to install this if
450 available. Make sure you install the development AND runtime versions
453 If you have to install lzo manually, you can get the source code
454 from @url{http://www.oberhumer.com/opensource/lzo/}. Instructions on how to configure,
455 build and install this package are included within the package. Please
456 make sure you build development and runtime libraries (which is the
460 @c ==================================================================
465 For the main event loop, tinc uses the libevent library.
467 If this library is not installed, you wil get an error when configuring
470 You can use your operating system's package manager to install this if
471 available. Make sure you install the development AND runtime versions
474 If you have to install libevent manually, you can get the source code
475 from @url{http://monkey.org/~provos/libevent/}. Instructions on how to configure,
476 build and install this package are included within the package. Please
477 make sure you build development and runtime libraries (which is the
490 @c ==================================================================
492 @chapter Installation
494 If you use Debian, you may want to install one of the
495 precompiled packages for your system. These packages are equipped with
496 system startup scripts and sample configurations.
498 If you cannot use one of the precompiled packages, or you want to compile tinc
499 for yourself, you can use the source. The source is distributed under
500 the GNU General Public License (GPL). Download the source from the
501 @uref{http://www.tinc-vpn.org/download, download page}, which has
502 the checksums of these files listed; you may wish to check these with
503 md5sum before continuing.
505 Tinc comes in a convenient autoconf/automake package, which you can just
506 treat the same as any other package. Which is just untar it, type
507 `./configure' and then `make'.
508 More detailed instructions are in the file @file{INSTALL}, which is
509 included in the source distribution.
512 * Building and installing tinc::
517 @c ==================================================================
518 @node Building and installing tinc
519 @section Building and installing tinc
521 Detailed instructions on configuring the source, building tinc and installing tinc
522 can be found in the file called @file{INSTALL}.
524 @cindex binary package
525 If you happen to have a binary package for tinc for your distribution,
526 you can use the package management tools of that distribution to install tinc.
527 The documentation that comes along with your distribution will tell you how to do that.
530 * Darwin (MacOS/X) build environment::
531 * Cygwin (Windows) build environment::
532 * MinGW (Windows) build environment::
536 @c ==================================================================
537 @node Darwin (MacOS/X) build environment
538 @subsection Darwin (MacOS/X) build environment
540 In order to build tinc on Darwin, you need to install the MacOS/X Developer Tools
541 from @uref{http://developer.apple.com/tools/macosxtools.html} and
542 a recent version of Fink from @uref{http://fink.sourceforge.net/}.
544 After installation use fink to download and install the following packages:
545 autoconf25, automake, dlcompat, m4, openssl, zlib and lzo.
547 @c ==================================================================
548 @node Cygwin (Windows) build environment
549 @subsection Cygwin (Windows) build environment
551 If Cygwin hasn't already been installed, install it directly from
552 @uref{http://www.cygwin.com/}.
554 When tinc is compiled in a Cygwin environment, it can only be run in this environment,
555 but all programs, including those started outside the Cygwin environment, will be able to use the VPN.
556 It will also support all features.
558 @c ==================================================================
559 @node MinGW (Windows) build environment
560 @subsection MinGW (Windows) build environment
562 You will need to install the MinGW environment from @uref{http://www.mingw.org}.
564 When tinc is compiled using MinGW it runs natively under Windows,
565 it is not necessary to keep MinGW installed.
567 When detaching, tinc will install itself as a service,
568 which will be restarted automatically after reboots.
571 @c ==================================================================
573 @section System files
575 Before you can run tinc, you must make sure you have all the needed
576 files on your system.
584 @c ==================================================================
586 @subsection Device files
589 Most operating systems nowadays come with the necessary device files by default,
590 or they have a mechanism to create them on demand.
592 If you use Linux and do not have udev installed,
593 you may need to create the following device file if it does not exist:
596 mknod -m 600 /dev/net/tun c 10 200
600 @c ==================================================================
602 @subsection Other files
604 @subsubheading @file{/etc/networks}
606 You may add a line to @file{/etc/networks} so that your VPN will get a
607 symbolic name. For example:
613 @subsubheading @file{/etc/services}
616 You may add this line to @file{/etc/services}. The effect is that you
617 may supply a @samp{tinc} as a valid port number to some programs. The
618 number 655 is registered with the IANA.
623 # Ivo Timmermans <ivo@@tinc-vpn.org>
638 @c ==================================================================
640 @chapter Configuration
643 * Configuration introduction::
644 * Multiple networks::
645 * How connections work::
646 * Configuration files::
647 * Generating keypairs::
648 * Network interfaces::
649 * Example configuration::
652 @c ==================================================================
653 @node Configuration introduction
654 @section Configuration introduction
656 Before actually starting to configure tinc and editing files,
657 make sure you have read this entire section so you know what to expect.
658 Then, make it clear to yourself how you want to organize your VPN:
659 What are the nodes (computers running tinc)?
660 What IP addresses/subnets do they have?
661 What is the network mask of the entire VPN?
662 Do you need special firewall rules?
663 Do you have to set up masquerading or forwarding rules?
664 Do you want to run tinc in router mode or switch mode?
665 These questions can only be answered by yourself,
666 you will not find the answers in this documentation.
667 Make sure you have an adequate understanding of networks in general.
668 @cindex Network Administrators Guide
669 A good resource on networking is the
670 @uref{http://www.linuxdoc.org/LDP/nag2/, Linux Network Administrators Guide}.
672 If you have everything clearly pictured in your mind,
673 proceed in the following order:
674 First, generate the configuration files (@file{tinc.conf}, your host configuration file, @file{tinc-up} and perhaps @file{tinc-down}).
675 Then generate the keypairs.
676 Finally, distribute the host configuration files.
677 These steps are described in the subsections below.
680 @c ==================================================================
681 @node Multiple networks
682 @section Multiple networks
684 @cindex multiple networks
686 In order to allow you to run more than one tinc daemon on one computer,
687 for instance if your computer is part of more than one VPN,
688 you can assign a @var{netname} to your VPN.
689 It is not required if you only run one tinc daemon,
690 it doesn't even have to be the same on all the sites of your VPN,
691 but it is recommended that you choose one anyway.
693 We will asume you use a netname throughout this document.
694 This means that you call tincd with the -n argument,
695 which will assign a netname to this daemon.
697 The effect of this is that the daemon will set its configuration
698 root to @file{@value{sysconfdir}/tinc/@var{netname}/}, where @var{netname} is your argument to the -n
699 option. You'll notice that it appears in syslog as @file{tinc.@var{netname}}.
701 However, it is not strictly necessary that you call tinc with the -n
702 option. In this case, the network name would just be empty, and it will
703 be used as such. tinc now looks for files in @file{@value{sysconfdir}/tinc/}, instead of
704 @file{@value{sysconfdir}/tinc/@var{netname}/}; the configuration file should be @file{@value{sysconfdir}/tinc/tinc.conf},
705 and the host configuration files are now expected to be in @file{@value{sysconfdir}/tinc/hosts/}.
707 But it is highly recommended that you use this feature of tinc, because
708 it will be so much clearer whom your daemon talks to. Hence, we will
709 assume that you use it.
712 @c ==================================================================
713 @node How connections work
714 @section How connections work
716 When tinc starts up, it parses the command-line options and then
717 reads in the configuration file tinc.conf.
718 If it sees one or more `ConnectTo' values pointing to other tinc daemons in that file,
719 it will try to connect to those other daemons.
720 Whether this succeeds or not and whether `ConnectTo' is specified or not,
721 tinc will listen for incoming connection from other deamons.
722 If you did specify a `ConnectTo' value and the other side is not responding,
723 tinc will keep retrying.
724 This means that once started, tinc will stay running until you tell it to stop,
725 and failures to connect to other tinc daemons will not stop your tinc daemon
726 for trying again later.
727 This means you don't have to intervene if there are temporary network problems.
731 There is no real distinction between a server and a client in tinc.
732 If you wish, you can view a tinc daemon without a `ConnectTo' value as a server,
733 and one which does specify such a value as a client.
734 It does not matter if two tinc daemons have a `ConnectTo' value pointing to each other however.
737 @c ==================================================================
738 @node Configuration files
739 @section Configuration files
741 The actual configuration of the daemon is done in the file
742 @file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf} and at least one other file in the directory
743 @file{@value{sysconfdir}/tinc/@var{netname}/hosts/}.
745 These file consists of comments (lines started with a #) or assignments
752 The variable names are case insensitive, and any spaces, tabs, newlines
753 and carriage returns are ignored. Note: it is not required that you put
754 in the `=' sign, but doing so improves readability. If you leave it
755 out, remember to replace it with at least one space character.
757 In this section all valid variables are listed in alphabetical order.
758 The default value is given between parentheses,
759 other comments are between square brackets.
762 * Main configuration variables::
763 * Host configuration variables::
769 @c ==================================================================
770 @node Main configuration variables
771 @subsection Main configuration variables
774 @cindex AddressFamily
775 @item AddressFamily = <ipv4|ipv6|any> (any)
776 This option affects the address family of listening and outgoing sockets.
777 If any is selected, then depending on the operating system
778 both IPv4 and IPv6 or just IPv6 listening sockets will be created.
780 @cindex BindToAddress
781 @item BindToAddress = <@var{address}> [experimental]
782 If your computer has more than one IPv4 or IPv6 address, tinc
783 will by default listen on all of them for incoming connections.
784 It is possible to bind only to a single address with this variable.
786 This option may not work on all platforms.
788 @cindex BindToInterface
789 @item BindToInterface = <@var{interface}> [experimental]
790 If you have more than one network interface in your computer, tinc will
791 by default listen on all of them for incoming connections. It is
792 possible to bind tinc to a single interface like eth0 or ppp0 with this
795 This option may not work on all platforms.
798 @item ConnectTo = <@var{name}>
799 Specifies which other tinc daemon to connect to on startup.
800 Multiple ConnectTo variables may be specified,
801 in which case outgoing connections to each specified tinc daemon are made.
802 The names should be known to this tinc daemon
803 (i.e., there should be a host configuration file for the name on the ConnectTo line).
805 If you don't specify a host with ConnectTo,
806 tinc won't try to connect to other daemons at all,
807 and will instead just listen for incoming connections.
810 @item Device = <@var{device}> (@file{/dev/tap0}, @file{/dev/net/tun} or other depending on platform)
811 The virtual network device to use.
812 Tinc will automatically detect what kind of device it is.
813 Note that you can only use one device per daemon.
814 Under Windows, use @var{Interface} instead of @var{Device}.
815 Note that you can only use one device per daemon.
816 See also @ref{Device files}.
819 @item DeviceType = <tun|tunnohead|tunifhead|tap> (only supported on BSD platforms)
820 The type of the virtual network device.
821 Tinc will normally automatically select the right type, and this option should not be used.
822 However, in case tinc does not seem to correctly interpret packets received from the virtual network device,
823 using this option might help.
828 Depending on the platform, this can either be with or without an address family header (see below).
832 Set type to tun without an address family header.
833 Tinc will expect packets read from the virtual network device to start with an IP header.
834 On some platforms IPv6 packets cannot be read from or written to the device in this mode.
838 Set type to tun with an address family header.
839 Tinc will expect packets read from the virtual network device
840 to start with a four byte header containing the address family,
841 followed by an IP header.
842 This mode should support both IPv4 and IPv6 packets.
846 Tinc will expect packets read from the virtual network device
847 to start with an Ethernet header.
850 @cindex GraphDumpFile
851 @item GraphDumpFile = <@var{filename}> [experimental]
852 If this option is present,
853 tinc will dump the current network graph to the file @var{filename}
854 every minute, unless there were no changes to the graph.
855 The file is in a format that can be read by graphviz tools.
856 If @var{filename} starts with a pipe symbol |,
857 then the rest of the filename is interpreted as a shell command
858 that is executed, the graph is then sent to stdin.
861 @item Hostnames = <yes|no> (no)
862 This option selects whether IP addresses (both real and on the VPN)
863 should be resolved. Since DNS lookups are blocking, it might affect
864 tinc's efficiency, even stopping the daemon for a few seconds everytime
865 it does a lookup if your DNS server is not responding.
867 This does not affect resolving hostnames to IP addresses from the
871 @item Interface = <@var{interface}>
872 Defines the name of the interface corresponding to the virtual network device.
873 Depending on the operating system and the type of device this may or may not actually set the name of the interface.
874 Under Windows, this variable is used to select which network interface will be used.
875 If you specified a Device, this variable is almost always already correctly set.
878 @item Mode = <router|switch|hub> (router)
879 This option selects the way packets are routed to other daemons.
885 variables in the host configuration files will be used to form a routing table.
886 Only unicast packets of routable protocols (IPv4 and IPv6) are supported in this mode.
888 This is the default mode, and unless you really know you need another mode, don't change it.
892 In this mode the MAC addresses of the packets on the VPN will be used to
893 dynamically create a routing table just like an Ethernet switch does.
894 Unicast, multicast and broadcast packets of every protocol that runs over Ethernet are supported in this mode
895 at the cost of frequent broadcast ARP requests and routing table updates.
897 This mode is primarily useful if you want to bridge Ethernet segments.
901 This mode is almost the same as the switch mode, but instead
902 every packet will be broadcast to the other daemons
903 while no routing table is managed.
907 @item KeyExpire = <@var{seconds}> (3600)
908 This option controls the time the encryption keys used to encrypt the data
909 are valid. It is common practice to change keys at regular intervals to
910 make it even harder for crackers, even though it is thought to be nearly
911 impossible to crack a single key.
914 @item MACExpire = <@var{seconds}> (600)
915 This option controls the amount of time MAC addresses are kept before they are removed.
916 This only has effect when Mode is set to "switch".
919 @item Name = <@var{name}> [required]
920 This is a symbolic name for this connection.
921 The name should consist only of alfanumeric and underscore characters (a-z, A-Z, 0-9 and _).
924 @item PingInterval = <@var{seconds}> (60)
925 The number of seconds of inactivity that tinc will wait before sending a
926 probe to the other end.
929 @item PingTimeout = <@var{seconds}> (5)
930 The number of seconds to wait for a response to pings or to allow meta
931 connections to block. If the other end doesn't respond within this time,
932 the connection is terminated, and the others will be notified of this.
934 @cindex PriorityInheritance
935 @item PriorityInheritance = <yes|no> (no) [experimental]
936 When this option is enabled the value of the TOS field of tunneled IPv4 packets
937 will be inherited by the UDP packets that are sent out.
940 @item PrivateKey = <@var{key}> [obsolete]
941 This is the RSA private key for tinc. However, for safety reasons it is
942 advised to store private keys of any kind in separate files. This prevents
943 accidental eavesdropping if you are editting the configuration file.
945 @cindex PrivateKeyFile
946 @item PrivateKeyFile = <@var{path}> (@file{@value{sysconfdir}/tinc/@var{netname}/rsa_key.priv})
947 This is the full path name of the RSA private key file that was
948 generated by @samp{tincctl generate-keys}. It must be a full path, not a
951 Note that there must be exactly one of PrivateKey
953 specified in the configuration file.
956 @item TunnelServer = <yes|no> (no) [experimental]
957 When this option is enabled tinc will no longer forward information between other tinc daemons,
958 and will only allow nodes and subnets on the VPN which are present in the
959 @file{@value{sysconfdir}/tinc/@var{netname}/hosts/} directory.
964 @c ==================================================================
965 @node Host configuration variables
966 @subsection Host configuration variables
970 @item Address = <@var{IP address}|@var{hostname}> [recommended]
971 This variable is only required if you want to connect to this host. It
972 must resolve to the external IP address where the host can be reached,
973 not the one that is internal to the VPN.
976 @item Cipher = <@var{cipher}> (blowfish)
977 The symmetric cipher algorithm used to encrypt UDP packets.
978 Any cipher supported by OpenSSL is recognized.
979 Furthermore, specifying "none" will turn off packet encryption.
980 It is best to use only those ciphers which support CBC mode.
983 @item Compression = <@var{level}> (0)
984 This option sets the level of compression used for UDP packets.
985 Possible values are 0 (off), 1 (fast zlib) and any integer up to 9 (best zlib),
986 10 (fast lzo) and 11 (best lzo).
989 @item Digest = <@var{digest}> (sha1)
990 The digest algorithm used to authenticate UDP packets.
991 Any digest supported by OpenSSL is recognized.
992 Furthermore, specifying "none" will turn off packet authentication.
995 @item IndirectData = <yes|no> (no)
996 This option specifies whether other tinc daemons besides the one you
997 specified with ConnectTo can make a direct connection to you. This is
998 especially useful if you are behind a firewall and it is impossible to
999 make a connection from the outside to your tinc daemon. Otherwise, it
1000 is best to leave this option out or set it to no.
1003 @item MACLength = <@var{bytes}> (4)
1004 The length of the message authentication code used to authenticate UDP packets.
1005 Can be anything from 0
1006 up to the length of the digest produced by the digest algorithm.
1009 @item PMTU = <@var{mtu}> (1514)
1010 This option controls the initial path MTU to this node.
1012 @cindex PMTUDiscovery
1013 @item PMTUDiscovery = <yes|no> (yes)
1014 When this option is enabled, tinc will try to discover the path MTU to this node.
1015 After the path MTU has been discovered, it will be enforced on the VPN.
1018 @item Port = <@var{port}> (655)
1019 This is the port this tinc daemon listens on.
1020 You can use decimal portnumbers or symbolic names (as listed in @file{/etc/services}).
1023 @item PublicKey = <@var{key}> [obsolete]
1024 This is the RSA public key for this host.
1026 @cindex PublicKeyFile
1027 @item PublicKeyFile = <@var{path}> [obsolete]
1028 This is the full path name of the RSA public key file that was generated
1029 by @samp{tincctl generate-keys}. It must be a full path, not a relative
1033 From version 1.0pre4 on tinc will store the public key directly into the
1034 host configuration file in PEM format, the above two options then are not
1035 necessary. Either the PEM format is used, or exactly
1036 @strong{one of the above two options} must be specified
1037 in each host configuration file, if you want to be able to establish a
1038 connection with that host.
1041 @item Subnet = <@var{address}[/@var{prefixlength}[#@var{weight}]]>
1042 The subnet which this tinc daemon will serve.
1043 Tinc tries to look up which other daemon it should send a packet to by searching the appropiate subnet.
1044 If the packet matches a subnet,
1045 it will be sent to the daemon who has this subnet in his host configuration file.
1046 Multiple subnet lines can be specified for each daemon.
1048 Subnets can either be single MAC, IPv4 or IPv6 addresses,
1049 in which case a subnet consisting of only that single address is assumed,
1050 or they can be a IPv4 or IPv6 network address with a prefixlength.
1051 Shorthand notations are not supported.
1052 For example, IPv4 subnets must be in a form like 192.168.1.0/24,
1053 where 192.168.1.0 is the network address and 24 is the number of bits set in the netmask.
1054 Note that subnets like 192.168.1.1/24 are invalid!
1055 Read a networking HOWTO/FAQ/guide if you don't understand this.
1056 IPv6 subnets are notated like fec0:0:0:1:0:0:0:0/64.
1057 MAC addresses are notated like 0:1a:2b:3c:4d:5e.
1059 @cindex CIDR notation
1060 Prefixlength is the number of bits set to 1 in the netmask part; for
1061 example: netmask 255.255.255.0 would become /24, 255.255.252.0 becomes
1062 /22. This conforms to standard CIDR notation as described in
1063 @uref{ftp://ftp.isi.edu/in-notes/rfc1519.txt, RFC1519}
1065 A Subnet can be given a weight to indicate its priority over identical Subnets
1066 owned by different nodes. The default weight is 10. Lower values indicate
1067 higher priority. Packets will be sent to the node with the highest priority,
1068 unless that node is not reachable, in which case the node with the next highest
1069 priority will be tried, and so on.
1072 @item TCPonly = <yes|no> (no)
1073 If this variable is set to yes, then the packets are tunnelled over a
1074 TCP connection instead of a UDP connection. This is especially useful
1075 for those who want to run a tinc daemon from behind a masquerading
1076 firewall, or if UDP packet routing is disabled somehow.
1077 Setting this options also implicitly sets IndirectData.
1081 @c ==================================================================
1086 Apart from reading the server and host configuration files,
1087 tinc can also run scripts at certain moments.
1088 Under Windows (not Cygwin), the scripts should have the extension .bat.
1092 @item @value{sysconfdir}/tinc/@var{netname}/tinc-up
1093 This is the most important script.
1094 If it is present it will be executed right after the tinc daemon has been
1095 started and has connected to the virtual network device.
1096 It should be used to set up the corresponding network interface,
1097 but can also be used to start other things.
1098 Under Windows you can use the Network Connections control panel instead of creating this script.
1101 @item @value{sysconfdir}/tinc/@var{netname}/tinc-down
1102 This script is started right before the tinc daemon quits.
1104 @item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-up
1105 This script is started when the tinc daemon with name @var{host} becomes reachable.
1107 @item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-down
1108 This script is started when the tinc daemon with name @var{host} becomes unreachable.
1110 @item @value{sysconfdir}/tinc/@var{netname}/host-up
1111 This script is started when any host becomes reachable.
1113 @item @value{sysconfdir}/tinc/@var{netname}/host-down
1114 This script is started when any host becomes unreachable.
1116 @item @value{sysconfdir}/tinc/@var{netname}/subnet-up
1117 This script is started when a Subnet becomes reachable.
1118 The Subnet and the node it belongs to are passed in environment variables.
1120 @item @value{sysconfdir}/tinc/@var{netname}/subnet-down
1121 This script is started when a Subnet becomes unreachable.
1124 @cindex environment variables
1125 The scripts are started without command line arguments,
1126 but can make use of certain environment variables.
1127 Under UNIX like operating systems the names of environment variables must be preceded by a $ in scripts.
1128 Under Windows, in @file{.bat} files, they have to be put between % signs.
1133 If a netname was specified, this environment variable contains it.
1137 Contains the name of this tinc daemon.
1141 Contains the name of the virtual network device that tinc uses.
1145 Contains the name of the virtual network interface that tinc uses.
1146 This should be used for commands like ifconfig.
1150 When a host becomes (un)reachable, this is set to its name.
1151 If a subnet becomes (un)reachable, this is set to the owner of that subnet.
1153 @cindex REMOTEADDRESS
1155 When a host becomes (un)reachable, this is set to its real address.
1159 When a host becomes (un)reachable,
1160 this is set to the port number it uses for communication with other tinc daemons.
1164 When a subnet becomes (un)reachable, this is set to the subnet.
1169 @c ==================================================================
1170 @node How to configure
1171 @subsection How to configure
1173 @subsubheading Step 1. Creating the main configuration file
1175 The main configuration file will be called @file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf}.
1176 Adapt the following example to create a basic configuration file:
1179 Name = @var{yourname}
1180 Device = @file{/dev/tap0}
1183 Then, if you know to which other tinc daemon(s) yours is going to connect,
1184 add `ConnectTo' values.
1186 @subsubheading Step 2. Creating your host configuration file
1188 If you added a line containing `Name = yourname' in the main configuarion file,
1189 you will need to create a host configuration file @file{@value{sysconfdir}/tinc/@var{netname}/hosts/yourname}.
1190 Adapt the following example to create a host configuration file:
1193 Address = your.real.hostname.org
1194 Subnet = 192.168.1.0/24
1197 You can also use an IP address instead of a hostname.
1198 The `Subnet' specifies the address range that is local for @emph{your part of the VPN only}.
1199 If you have multiple address ranges you can specify more than one `Subnet'.
1200 You might also need to add a `Port' if you want your tinc daemon to run on a different port number than the default (655).
1203 @c ==================================================================
1204 @node Generating keypairs
1205 @section Generating keypairs
1207 @cindex key generation
1208 Now that you have already created the main configuration file and your host configuration file,
1209 you can easily create a public/private keypair by entering the following command:
1212 tincctl -n @var{netname} generate-keys
1215 Tinc will generate a public and a private key and ask you where to put them.
1216 Just press enter to accept the defaults.
1219 @c ==================================================================
1220 @node Network interfaces
1221 @section Network interfaces
1223 Before tinc can start transmitting data over the tunnel, it must
1224 set up the virtual network interface.
1226 First, decide which IP addresses you want to have associated with these
1227 devices, and what network mask they must have.
1229 Tinc will open a virtual network device (@file{/dev/tun}, @file{/dev/tap0} or similar),
1230 which will also create a network interface called something like @samp{tun0}, @samp{tap0}.
1231 If you are using the Linux tun/tap driver, the network interface will by default have the same name as the @var{netname}.
1232 Under Windows you can change the name of the network interface from the Network Connections control panel.
1235 You can configure the network interface by putting ordinary ifconfig, route, and other commands
1236 to a script named @file{@value{sysconfdir}/tinc/@var{netname}/tinc-up}.
1237 When tinc starts, this script will be executed. When tinc exits, it will execute the script named
1238 @file{@value{sysconfdir}/tinc/@var{netname}/tinc-down}, but normally you don't need to create that script.
1240 An example @file{tinc-up} script:
1244 ifconfig $INTERFACE 192.168.1.1 netmask 255.255.0.0
1247 This script gives the interface an IP address and a netmask.
1248 The kernel will also automatically add a route to this interface, so normally you don't need
1249 to add route commands to the @file{tinc-up} script.
1250 The kernel will also bring the interface up after this command.
1252 The netmask is the mask of the @emph{entire} VPN network, not just your
1255 The exact syntax of the ifconfig and route commands differs from platform to platform.
1256 You can look up the commands for setting addresses and adding routes in @ref{Platform specific information},
1257 but it is best to consult the manpages of those utilities on your platform.
1260 @c ==================================================================
1261 @node Example configuration
1262 @section Example configuration
1266 Imagine the following situation. Branch A of our example `company' wants to connect
1267 three branch offices in B, C and D using the Internet. All four offices
1268 have a 24/7 connection to the Internet.
1270 A is going to serve as the center of the network. B and C will connect
1271 to A, and D will connect to C. Each office will be assigned their own IP
1275 A: net 10.1.0.0 mask 255.255.0.0 gateway 10.1.54.1 internet IP 1.2.3.4
1276 B: net 10.2.0.0 mask 255.255.0.0 gateway 10.2.1.12 internet IP 2.3.4.5
1277 C: net 10.3.0.0 mask 255.255.0.0 gateway 10.3.69.254 internet IP 3.4.5.6
1278 D: net 10.4.0.0 mask 255.255.0.0 gateway 10.4.3.32 internet IP 4.5.6.7
1281 Here, ``gateway'' is the VPN IP address of the machine that is running the
1282 tincd, and ``internet IP'' is the IP address of the firewall, which does not
1283 need to run tincd, but it must do a port forwarding of TCP and UDP on port
1284 655 (unless otherwise configured).
1286 In this example, it is assumed that eth0 is the interface that points to
1287 the inner (physical) LAN of the office, although this could also be the
1288 same as the interface that leads to the Internet. The configuration of
1289 the real interface is also shown as a comment, to give you an idea of
1290 how these example host is set up. All branches use the netname `company'
1291 for this particular VPN.
1293 @subsubheading For Branch A
1295 @emph{BranchA} would be configured like this:
1297 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1300 # Real interface of internal network:
1301 # ifconfig eth0 10.1.54.1 netmask 255.255.0.0
1303 ifconfig $INTERFACE 10.1.54.1 netmask 255.0.0.0
1306 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1313 On all hosts, @file{@value{sysconfdir}/tinc/company/hosts/BranchA} contains:
1316 Subnet = 10.1.0.0/16
1319 -----BEGIN RSA PUBLIC KEY-----
1321 -----END RSA PUBLIC KEY-----
1324 Note that the IP addresses of eth0 and tap0 are the same.
1325 This is quite possible, if you make sure that the netmasks of the interfaces are different.
1326 It is in fact recommended to give give both real internal network interfaces and tap interfaces the same IP address,
1327 since that will make things a lot easier to remember and set up.
1330 @subsubheading For Branch B
1332 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1335 # Real interface of internal network:
1336 # ifconfig eth0 10.2.43.8 netmask 255.255.0.0
1338 ifconfig $INTERFACE 10.2.1.12 netmask 255.0.0.0
1341 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1348 Note here that the internal address (on eth0) doesn't have to be the
1349 same as on the tap0 device. Also, ConnectTo is given so that no-one can
1350 connect to this node.
1352 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchB}:
1355 Subnet = 10.2.0.0/16
1358 -----BEGIN RSA PUBLIC KEY-----
1360 -----END RSA PUBLIC KEY-----
1364 @subsubheading For Branch C
1366 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1369 # Real interface of internal network:
1370 # ifconfig eth0 10.3.69.254 netmask 255.255.0.0
1372 ifconfig $INTERFACE 10.3.69.254 netmask 255.0.0.0
1375 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1383 C already has another daemon that runs on port 655, so they have to
1384 reserve another port for tinc. It knows the portnumber it has to listen on
1385 from it's own host configuration file.
1387 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchC}:
1391 Subnet = 10.3.0.0/16
1394 -----BEGIN RSA PUBLIC KEY-----
1396 -----END RSA PUBLIC KEY-----
1400 @subsubheading For Branch D
1402 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1405 # Real interface of internal network:
1406 # ifconfig eth0 10.4.3.32 netmask 255.255.0.0
1408 ifconfig $INTERFACE 10.4.3.32 netmask 255.0.0.0
1411 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1416 Device = /dev/net/tun
1419 D will be connecting to C, which has a tincd running for this network on
1420 port 2000. It knows the port number from the host configuration file.
1421 Also note that since D uses the tun/tap driver, the network interface
1422 will not be called `tun' or `tap0' or something like that, but will
1423 have the same name as netname.
1425 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchD}:
1428 Subnet = 10.4.0.0/16
1431 -----BEGIN RSA PUBLIC KEY-----
1433 -----END RSA PUBLIC KEY-----
1436 @subsubheading Key files
1438 A, B, C and D all have generated a public/private keypair with the following command:
1441 tincctl -n company generate-keys
1444 The private key is stored in @file{@value{sysconfdir}/tinc/company/rsa_key.priv},
1445 the public key is put into the host configuration file in the @file{@value{sysconfdir}/tinc/company/hosts/} directory.
1446 During key generation, tinc automatically guesses the right filenames based on the -n option and
1447 the Name directive in the @file{tinc.conf} file (if it is available).
1449 @subsubheading Starting
1451 After each branch has finished configuration and they have distributed
1452 the host configuration files amongst them, they can start their tinc daemons.
1453 They don't necessarily have to wait for the other branches to have started
1454 their daemons, tinc will try connecting until they are available.
1457 @c ==================================================================
1459 @chapter Running tinc
1461 If everything else is done, you can start tinc by typing the following command:
1464 tincd -n @var{netname}
1468 Tinc will detach from the terminal and continue to run in the background like a good daemon.
1469 If there are any problems however you can try to increase the debug level
1470 and look in the syslog to find out what the problems are.
1476 * Solving problems::
1478 * Sending bug reports::
1482 @c ==================================================================
1483 @node Runtime options
1484 @section Runtime options
1486 Besides the settings in the configuration file, tinc also accepts some
1487 command line options.
1489 @cindex command line
1490 @cindex runtime options
1494 @item -c, --config=@var{path}
1495 Read configuration options from the directory @var{path}. The default is
1496 @file{@value{sysconfdir}/tinc/@var{netname}/}.
1498 @item -D, --no-detach
1499 Don't fork and detach.
1500 This will also disable the automatic restart mechanism for fatal errors.
1503 @item -d, --debug=@var{level}
1504 Set debug level to @var{level}. The higher the debug level, the more gets
1505 logged. Everything goes via syslog.
1507 @item -n, --net=@var{netname}
1508 Use configuration for net @var{netname}. @xref{Multiple networks}.
1510 @item --controlsocket=@var{filename}
1511 Open control socket at @var{filename}. If unspecified, the default is
1512 @file{@value{localstatedir}/run/tinc.@var{netname}.control}.
1515 Lock tinc into main memory.
1516 This will prevent sensitive data like shared private keys to be written to the system swap files/partitions.
1518 @item --logfile[=@var{file}]
1519 Write log entries to a file instead of to the system logging facility.
1520 If @var{file} is omitted, the default is @file{@value{localstatedir}/log/tinc.@var{netname}.log}.
1522 @item --bypass-security
1523 Disables encryption and authentication.
1524 Only useful for debugging.
1527 Display a short reminder of these runtime options and terminate.
1530 Output version information and exit.
1534 @c ==================================================================
1539 You can also send the following signals to a running tincd process:
1545 Partially rereads configuration files.
1546 Connections to hosts whose host config file are removed are closed.
1547 New outgoing connections specified in @file{tinc.conf} will be made.
1551 @c ==================================================================
1553 @section Debug levels
1555 @cindex debug levels
1556 The tinc daemon can send a lot of messages to the syslog.
1557 The higher the debug level, the more messages it will log.
1558 Each level inherits all messages of the previous level:
1564 This will log a message indicating tinc has started along with a version number.
1565 It will also log any serious error.
1568 This will log all connections that are made with other tinc daemons.
1571 This will log status and error messages from scripts and other tinc daemons.
1574 This will log all requests that are exchanged with other tinc daemons. These include
1575 authentication, key exchange and connection list updates.
1578 This will log a copy of everything received on the meta socket.
1581 This will log all network traffic over the virtual private network.
1585 @c ==================================================================
1586 @node Solving problems
1587 @section Solving problems
1589 If tinc starts without problems, but if the VPN doesn't work, you will have to find the cause of the problem.
1590 The first thing to do is to start tinc with a high debug level in the foreground,
1591 so you can directly see everything tinc logs:
1594 tincd -n @var{netname} -d5 -D
1597 If tinc does not log any error messages, then you might want to check the following things:
1600 @item @file{tinc-up} script
1601 Does this script contain the right commands?
1602 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.
1605 Does the Subnet (or Subnets) in the host configuration file of this host match the portion of the VPN that belongs to this host?
1607 @item Firewalls and NATs
1608 Do you have a firewall or a NAT device (a masquerading firewall or perhaps an ADSL router that performs masquerading)?
1609 If so, check that it allows TCP and UDP traffic on port 655.
1610 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.
1611 You can add @samp{TCPOnly = yes} to your host config file to force tinc to only use a single TCP connection,
1612 this works through most firewalls and NATs.
1617 @c ==================================================================
1618 @node Error messages
1619 @section Error messages
1621 What follows is a list of the most common error messages you might find in the logs.
1622 Some of them will only be visible if the debug level is high enough.
1625 @item Could not open /dev/tap0: No such device
1628 @item You forgot to `modprobe netlink_dev' or `modprobe ethertap'.
1629 @item You forgot to compile `Netlink device emulation' in the kernel.
1632 @item Can't write to /dev/net/tun: No such device
1635 @item You forgot to `modprobe tun'.
1636 @item You forgot to compile `Universal TUN/TAP driver' in the kernel.
1637 @item The tun device is located somewhere else in @file{/dev/}.
1640 @item Network address and prefix length do not match!
1643 @item The Subnet field must contain a @emph{network} address, trailing bits should be 0.
1644 @item If you only want to use one IP address, set the netmask to /32.
1647 @item Error reading RSA key file `rsa_key.priv': No such file or directory
1650 @item You forgot to create a public/private keypair.
1651 @item Specify the complete pathname to the private key file with the @samp{PrivateKeyFile} option.
1654 @item Warning: insecure file permissions for RSA private key file `rsa_key.priv'!
1657 @item The private key file is readable by users other than root.
1658 Use chmod to correct the file permissions.
1661 @item Creating metasocket failed: Address family not supported
1664 @item By default tinc tries to create both IPv4 and IPv6 sockets.
1665 On some platforms this might not be implemented.
1666 If the logs show @samp{Ready} later on, then at least one metasocket was created,
1667 and you can ignore this message.
1668 You can add @samp{AddressFamily = ipv4} to @file{tinc.conf} to prevent this from happening.
1671 @item Cannot route packet: unknown IPv4 destination 1.2.3.4
1674 @item You try to send traffic to a host on the VPN for which no Subnet is known.
1675 @item If it is a broadcast address (ending in .255), it probably is a samba server or a Windows host sending broadcast packets.
1679 @item Cannot route packet: ARP request for unknown address 1.2.3.4
1682 @item You try to send traffic to a host on the VPN for which no Subnet is known.
1685 @item Packet with destination 1.2.3.4 is looping back to us!
1688 @item Something is not configured right. Packets are being sent out to the
1689 virtual network device, but according to the Subnet directives in your host configuration
1690 file, those packets should go to your own host. Most common mistake is that
1691 you have a Subnet line in your host configuration file with a prefix length which is
1692 just as large as the prefix of the virtual network interface. The latter should in almost all
1693 cases be larger. Rethink your configuration.
1694 Note that you will only see this message if you specified a debug
1695 level of 5 or higher!
1696 @item Chances are that a @samp{Subnet = ...} line in the host configuration file of this tinc daemon is wrong.
1697 Change it to a subnet that is accepted locally by another interface,
1698 or if that is not the case, try changing the prefix length into /32.
1701 @item Node foo (1.2.3.4) is not reachable
1704 @item Node foo does not have a connection anymore, its tinc daemon is not running or its connection to the Internet is broken.
1707 @item Received UDP packet from unknown source 1.2.3.4 (port 12345)
1710 @item If you see this only sporadically, it is harmless and caused by a node sending packets using an old key.
1711 @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.
1712 You can add @samp{TCPOnly = yes} to host configuration files to force all VPN traffic to go over a TCP connection.
1715 @item Got bad/bogus/unauthorized REQUEST from foo (1.2.3.4 port 12345)
1718 @item Node foo does not have the right public/private keypair.
1719 Generate new keypairs and distribute them again.
1720 @item An attacker tries to gain access to your VPN.
1721 @item A network error caused corruption of metadata sent from foo.
1726 @c ==================================================================
1727 @node Sending bug reports
1728 @section Sending bug reports
1730 If you really can't find the cause of a problem, or if you suspect tinc is not working right,
1731 you can send us a bugreport, see @ref{Contact information}.
1732 Be sure to include the following information in your bugreport:
1735 @item A clear description of what you are trying to achieve and what the problem is.
1736 @item What platform (operating system, version, hardware architecture) and which version of tinc you use.
1737 @item If compiling tinc fails, a copy of @file{config.log} and the error messages you get.
1738 @item Otherwise, a copy of @file{tinc.conf}, @file{tinc-up} and all files in the @file{hosts/} directory.
1739 @item The output of the commands @samp{ifconfig -a} and @samp{route -n} (or @samp{netstat -rn} if that doesn't work).
1740 @item The output of any command that fails to work as it should (like ping or traceroute).
1743 @c ==================================================================
1744 @node Controlling tinc
1745 @chapter Controlling tinc
1747 You can control and inspect a running @samp{tincd} through the @samp{tincctl}
1748 command. A quick example:
1751 tincctl -n @var{netname} reload
1755 * tincctl runtime options::
1756 * tincctl commands::
1760 @c ==================================================================
1761 @node tincctl runtime options
1762 @section tincctl runtime options
1766 @item -c, --config=@var{path}
1767 Read configuration options from the directory @var{path}. The default is
1768 @file{@value{sysconfdir}/tinc/@var{netname}/}.
1770 @item -n, --net=@var{netname}
1771 Use configuration for net @var{netname}. @xref{Multiple networks}.
1773 @item --controlsocket=@var{filename}
1774 Open control socket at @var{filename}. If unspecified, the default is
1775 @file{@value{localstatedir}/run/tinc.@var{netname}.control}.
1778 Display a short reminder of runtime options and commands, then terminate.
1781 Output version information and exit.
1786 @c ==================================================================
1787 @node tincctl commands
1788 @section tincctl commands
1800 Restart @samp{tincd}.
1803 Partially rereads configuration files. Connections to hosts whose host
1804 config files are removed are closed. New outgoing connections specified
1805 in @file{tinc.conf} will be made.
1808 Shows the PID of the currently running @samp{tincd}.
1810 @item generate-keys [@var{bits}]
1811 Generate public/private keypair of @var{bits} length. If @var{bits} is not specified,
1812 1024 is the default. tinc will ask where you want to store the files,
1813 but will default to the configuration directory (you can use the -c or -n
1817 Dump a list of all known nodes in the VPN.
1820 Dump a list of all known connections in the VPN.
1823 Dump a list of all known subnets in the VPN.
1825 @item dump connections
1826 Dump a list of all meta connections with ourself.
1829 Dump a graph of the VPN in dotty format.
1832 Purges all information remembered about unreachable nodes.
1834 @item debug @var{level}
1835 Sets debug level to @var{level}.
1838 Forces tinc to try to connect to all uplinks immediately.
1839 Usually tinc attempts to do this itself,
1840 but increases the time it waits between the attempts each time it failed,
1841 and if tinc didn't succeed to connect to an uplink the first time after it started,
1842 it defaults to the maximum time of 15 minutes.
1847 @c ==================================================================
1848 @node Technical information
1849 @chapter Technical information
1854 * The meta-protocol::
1859 @c ==================================================================
1860 @node The connection
1861 @section The connection
1864 Tinc is a daemon that takes VPN data and transmit that to another host
1865 computer over the existing Internet infrastructure.
1869 * The meta-connection::
1873 @c ==================================================================
1874 @node The UDP tunnel
1875 @subsection The UDP tunnel
1877 @cindex virtual network device
1879 The data itself is read from a character device file, the so-called
1880 @emph{virtual network device}. This device is associated with a network
1881 interface. Any data sent to this interface can be read from the device,
1882 and any data written to the device gets sent from the interface.
1883 There are two possible types of virtual network devices:
1884 `tun' style, which are point-to-point devices which can only handle IPv4 and/or IPv6 packets,
1885 and `tap' style, which are Ethernet devices and handle complete Ethernet frames.
1887 So when tinc reads an Ethernet frame from the device, it determines its
1888 type. When tinc is in it's default routing mode, it can handle IPv4 and IPv6
1889 packets. Depending on the Subnet lines, it will send the packets off to their destination IP address.
1890 In the `switch' and `hub' mode, tinc will use broadcasts and MAC address discovery
1891 to deduce the destination of the packets.
1892 Since the latter modes only depend on the link layer information,
1893 any protocol that runs over Ethernet is supported (for instance IPX and Appletalk).
1894 However, only `tap' style devices provide this information.
1896 After the destination has been determined,
1897 the packet will be compressed (optionally),
1898 a sequence number will be added to the packet,
1899 the packet will then be encrypted
1900 and a message authentication code will be appended.
1902 @cindex encapsulating
1904 When that is done, time has come to actually transport the
1905 packet to the destination computer. We do this by sending the packet
1906 over an UDP connection to the destination host. This is called
1907 @emph{encapsulating}, the VPN packet (though now encrypted) is
1908 encapsulated in another IP datagram.
1910 When the destination receives this packet, the same thing happens, only
1911 in reverse. So it checks the message authentication code, decrypts the contents of the UDP datagram,
1912 checks the sequence number
1913 and writes the decrypted information to its own virtual network device.
1915 If the virtual network device is a `tun' device (a point-to-point tunnel),
1916 there is no problem for the kernel to accept a packet.
1917 However, if it is a `tap' device (this is the only available type on FreeBSD),
1918 the destination MAC address must match that of the virtual network interface.
1919 If tinc is in it's default routing mode, ARP does not work, so the correct destination MAC
1920 can not be known by the sending host.
1921 Tinc solves this by letting the receiving end detect the MAC address of its own virtual network interface
1922 and overwriting the destination MAC address of the received packet.
1924 In switch or hub modes ARP does work so the sender already knows the correct destination MAC address.
1925 In those modes every interface should have a unique MAC address, so make sure they are not the same.
1926 Because switch and hub modes rely on MAC addresses to function correctly,
1927 these modes cannot be used on the following operating systems which don't have a `tap' style virtual network device:
1928 OpenBSD, NetBSD, Darwin and Solaris.
1931 @c ==================================================================
1932 @node The meta-connection
1933 @subsection The meta-connection
1935 Having only a UDP connection available is not enough. Though suitable
1936 for transmitting data, we want to be able to reliably send other
1937 information, such as routing and session key information to somebody.
1940 TCP is a better alternative, because it already contains protection
1941 against information being lost, unlike UDP.
1943 So we establish two connections. One for the encrypted VPN data, and one
1944 for other information, the meta-data. Hence, we call the second
1945 connection the meta-connection. We can now be sure that the
1946 meta-information doesn't get lost on the way to another computer.
1948 @cindex data-protocol
1949 @cindex meta-protocol
1950 Like with any communication, we must have a protocol, so that everybody
1951 knows what everything stands for, and how she should react. Because we
1952 have two connections, we also have two protocols. The protocol used for
1953 the UDP data is the ``data-protocol,'' the other one is the
1956 The reason we don't use TCP for both protocols is that UDP is much
1957 better for encapsulation, even while it is less reliable. The real
1958 problem is that when TCP would be used to encapsulate a TCP stream
1959 that's on the private network, for every packet sent there would be
1960 three ACKs sent instead of just one. Furthermore, if there would be
1961 a timeout, both TCP streams would sense the timeout, and both would
1962 start re-sending packets.
1965 @c ==================================================================
1966 @node The meta-protocol
1967 @section The meta-protocol
1969 The meta protocol is used to tie all tinc daemons together, and
1970 exchange information about which tinc daemon serves which virtual
1973 The meta protocol consists of requests that can be sent to the other
1974 side. Each request has a unique number and several parameters. All
1975 requests are represented in the standard ASCII character set. It is
1976 possible to use tools such as telnet or netcat to connect to a tinc
1977 daemon started with the --bypass-security option
1978 and to read and write requests by hand, provided that one
1979 understands the numeric codes sent.
1981 The authentication scheme is described in @ref{Authentication protocol}. After a
1982 successful authentication, the server and the client will exchange all the
1983 information about other tinc daemons and subnets they know of, so that both
1984 sides (and all the other tinc daemons behind them) have their information
1991 ------------------------------------------------------------------
1992 ADD_EDGE node1 node2 21.32.43.54 655 222 0
1993 | | | | | +-> options
1994 | | | | +----> weight
1995 | | | +--------> UDP port of node2
1996 | | +----------------> real address of node2
1997 | +-------------------------> name of destination node
1998 +-------------------------------> name of source node
2000 ADD_SUBNET node 192.168.1.0/24
2001 | | +--> prefixlength
2002 | +--------> network address
2003 +------------------> owner of this subnet
2004 ------------------------------------------------------------------
2007 The ADD_EDGE messages are to inform other tinc daemons that a connection between
2008 two nodes exist. The address of the destination node is available so that
2009 VPN packets can be sent directly to that node.
2011 The ADD_SUBNET messages inform other tinc daemons that certain subnets belong
2012 to certain nodes. tinc will use it to determine to which node a VPN packet has
2019 ------------------------------------------------------------------
2020 DEL_EDGE node1 node2
2021 | +----> name of destination node
2022 +----------> name of source node
2024 DEL_SUBNET node 192.168.1.0/24
2025 | | +--> prefixlength
2026 | +--------> network address
2027 +------------------> owner of this subnet
2028 ------------------------------------------------------------------
2031 In case a connection between two daemons is closed or broken, DEL_EDGE messages
2032 are sent to inform the other daemons of that fact. Each daemon will calculate a
2033 new route to the the daemons, or mark them unreachable if there isn't any.
2040 ------------------------------------------------------------------
2041 REQ_KEY origin destination
2042 | +--> name of the tinc daemon it wants the key from
2043 +----------> name of the daemon that wants the key
2045 ANS_KEY origin destination 4ae0b0a82d6e0078 91 64 4
2046 | | \______________/ | | +--> MAC length
2047 | | | | +-----> digest algorithm
2048 | | | +--------> cipher algorithm
2049 | | +--> 128 bits key
2050 | +--> name of the daemon that wants the key
2051 +----------> name of the daemon that uses this key
2054 +--> daemon that has changed it's packet key
2055 ------------------------------------------------------------------
2058 The keys used to encrypt VPN packets are not sent out directly. This is
2059 because it would generate a lot of traffic on VPNs with many daemons, and
2060 chances are that not every tinc daemon will ever send a packet to every
2061 other daemon. Instead, if a daemon needs a key it sends a request for it
2062 via the meta connection of the nearest hop in the direction of the
2069 ------------------------------------------------------------------
2072 ------------------------------------------------------------------
2075 There is also a mechanism to check if hosts are still alive. Since network
2076 failures or a crash can cause a daemon to be killed without properly
2077 shutting down the TCP connection, this is necessary to keep an up to date
2078 connection list. PINGs are sent at regular intervals, except when there
2079 is also some other traffic. A little bit of salt (random data) is added
2080 with each PING and PONG message, to make sure that long sequences of PING/PONG
2081 messages without any other traffic won't result in known plaintext.
2083 This basically covers what is sent over the meta connection by tinc.
2086 @c ==================================================================
2092 Tinc got its name from ``TINC,'' short for @emph{There Is No Cabal}; the
2093 alleged Cabal was/is an organisation that was said to keep an eye on the
2094 entire Internet. As this is exactly what you @emph{don't} want, we named
2095 the tinc project after TINC.
2098 But in order to be ``immune'' to eavesdropping, you'll have to encrypt
2099 your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does
2100 exactly that: encrypt.
2101 Tinc by default uses blowfish encryption with 128 bit keys in CBC mode, 32 bit
2102 sequence numbers and 4 byte long message authentication codes to make sure
2103 eavesdroppers cannot get and cannot change any information at all from the
2104 packets they can intercept. The encryption algorithm and message authentication
2105 algorithm can be changed in the configuration. The length of the message
2106 authentication codes is also adjustable. The length of the key for the
2107 encryption algorithm is always the default length used by OpenSSL.
2110 * Authentication protocol::
2111 * Encryption of network packets::
2116 @c ==================================================================
2117 @node Authentication protocol
2118 @subsection Authentication protocol
2120 @cindex authentication
2121 A new scheme for authentication in tinc has been devised, which offers some
2122 improvements over the protocol used in 1.0pre2 and 1.0pre3. Explanation is
2132 --------------------------------------------------------------------------
2133 client <attempts connection>
2135 server <accepts connection>
2139 +-------> name of tinc daemon
2143 +-------> name of tinc daemon
2145 client META_KEY 5f0823a93e35b69e...7086ec7866ce582b
2146 \_________________________________/
2147 +-> RSAKEYLEN bits totally random string S1,
2148 encrypted with server's public RSA key
2150 server META_KEY 6ab9c1640388f8f0...45d1a07f8a672630
2151 \_________________________________/
2152 +-> RSAKEYLEN bits totally random string S2,
2153 encrypted with client's public RSA key
2156 - the client will symmetrically encrypt outgoing traffic using S1
2157 - the server will symmetrically encrypt outgoing traffic using S2
2159 client CHALLENGE da02add1817c1920989ba6ae2a49cecbda0
2160 \_________________________________/
2161 +-> CHALLEN bits totally random string H1
2163 server CHALLENGE 57fb4b2ccd70d6bb35a64c142f47e61d57f
2164 \_________________________________/
2165 +-> CHALLEN bits totally random string H2
2167 client CHAL_REPLY 816a86
2168 +-> 160 bits SHA1 of H2
2170 server CHAL_REPLY 928ffe
2171 +-> 160 bits SHA1 of H1
2173 After the correct challenge replies are received, both ends have proved
2174 their identity. Further information is exchanged.
2176 client ACK 655 123 0
2178 | +----> estimated weight
2179 +--------> listening port of client
2181 server ACK 655 321 0
2183 | +----> estimated weight
2184 +--------> listening port of server
2185 --------------------------------------------------------------------------
2188 This new scheme has several improvements, both in efficiency and security.
2190 First of all, the server sends exactly the same kind of messages over the wire
2191 as the client. The previous versions of tinc first authenticated the client,
2192 and then the server. This scheme even allows both sides to send their messages
2193 simultaneously, there is no need to wait for the other to send something first.
2194 This means that any calculations that need to be done upon sending or receiving
2195 a message can also be done in parallel. This is especially important when doing
2196 RSA encryption/decryption. Given that these calculations are the main part of
2197 the CPU time spent for the authentication, speed is improved by a factor 2.
2199 Second, only one RSA encrypted message is sent instead of two. This reduces the
2200 amount of information attackers can see (and thus use for a cryptographic
2201 attack). It also improves speed by a factor two, making the total speedup a
2204 Third, and most important:
2205 The symmetric cipher keys are exchanged first, the challenge is done
2206 afterwards. In the previous authentication scheme, because a man-in-the-middle
2207 could pass the challenge/chal_reply phase (by just copying the messages between
2208 the two real tinc daemons), but no information was exchanged that was really
2209 needed to read the rest of the messages, the challenge/chal_reply phase was of
2210 no real use. The man-in-the-middle was only stopped by the fact that only after
2211 the ACK messages were encrypted with the symmetric cipher. Potentially, it
2212 could even send it's own symmetric key to the server (if it knew the server's
2213 public key) and read some of the metadata the server would send it (it was
2214 impossible for the mitm to read actual network packets though). The new scheme
2215 however prevents this.
2217 This new scheme makes sure that first of all, symmetric keys are exchanged. The
2218 rest of the messages are then encrypted with the symmetric cipher. Then, each
2219 side can only read received messages if they have their private key. The
2220 challenge is there to let the other side know that the private key is really
2221 known, because a challenge reply can only be sent back if the challenge is
2222 decrypted correctly, and that can only be done with knowledge of the private
2225 Fourth: the first thing that is sent via the symmetric cipher encrypted
2226 connection is a totally random string, so that there is no known plaintext (for
2227 an attacker) in the beginning of the encrypted stream.
2230 @c ==================================================================
2231 @node Encryption of network packets
2232 @subsection Encryption of network packets
2235 A data packet can only be sent if the encryption key is known to both
2236 parties, and the connection is activated. If the encryption key is not
2237 known, a request is sent to the destination using the meta connection
2238 to retrieve it. The packet is stored in a queue while waiting for the
2242 The UDP packet containing the network packet from the VPN has the following layout:
2245 ... | IP header | UDP header | seqno | VPN packet | MAC | UDP trailer
2246 \___________________/\_____/
2248 V +---> digest algorithm
2249 Encrypted with symmetric cipher
2252 So, the entire VPN packet is encrypted using a symmetric cipher, including a 32 bits
2253 sequence number that is added in front of the actual VPN packet, to act as a unique
2254 IV for each packet and to prevent replay attacks. A message authentication code
2255 is added to the UDP packet to prevent alteration of packets. By default the
2256 first 4 bytes of the digest are used for this, but this can be changed using
2257 the MACLength configuration variable.
2259 @c ==================================================================
2260 @node Security issues
2261 @subsection Security issues
2263 In August 2000, we discovered the existence of a security hole in all versions
2264 of tinc up to and including 1.0pre2. This had to do with the way we exchanged
2265 keys. Since then, we have been working on a new authentication scheme to make
2266 tinc as secure as possible. The current version uses the OpenSSL library and
2267 uses strong authentication with RSA keys.
2269 On the 29th of December 2001, Jerome Etienne posted a security analysis of tinc
2270 1.0pre4. Due to a lack of sequence numbers and a message authentication code
2271 for each packet, an attacker could possibly disrupt certain network services or
2272 launch a denial of service attack by replaying intercepted packets. The current
2273 version adds sequence numbers and message authentication codes to prevent such
2276 On the 15th of September 2003, Peter Gutmann posted a security analysis of tinc
2277 1.0.1. He argues that the 32 bit sequence number used by tinc is not a good IV,
2278 that tinc's default length of 4 bytes for the MAC is too short, and he doesn't
2279 like tinc's use of RSA during authentication. We do not know of a security hole
2280 in this version of tinc, but tinc's security is not as strong as TLS or IPsec.
2281 We will address these issues in tinc 2.0.
2283 Cryptography is a hard thing to get right. We cannot make any
2284 guarantees. Time, review and feedback are the only things that can
2285 prove the security of any cryptographic product. If you wish to review
2286 tinc or give us feedback, you are stronly encouraged to do so.
2289 @c ==================================================================
2290 @node Platform specific information
2291 @chapter Platform specific information
2294 * Interface configuration::
2298 @c ==================================================================
2299 @node Interface configuration
2300 @section Interface configuration
2302 When configuring an interface, one normally assigns it an address and a
2303 netmask. The address uniquely identifies the host on the network attached to
2304 the interface. The netmask, combined with the address, forms a subnet. It is
2305 used to add a route to the routing table instructing the kernel to send all
2306 packets which fall into that subnet to that interface. Because all packets for
2307 the entire VPN should go to the virtual network interface used by tinc, the
2308 netmask should be such that it encompasses the entire VPN.
2312 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2314 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2315 @item Linux iproute2
2316 @tab @code{ip addr add} @var{address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2318 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2320 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2322 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2324 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2325 @item Darwin (MacOS/X)
2326 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2328 @tab @code{netsh interface ip set address} @var{interface} @code{static} @var{address} @var{netmask}
2334 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2336 @tab @code{ifconfig} @var{interface} @code{add} @var{address}@code{/}@var{prefixlength}
2338 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2340 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2342 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2344 @tab @code{ifconfig} @var{interface} @code{inet6 plumb up}
2346 @tab @code{ifconfig} @var{interface} @code{inet6 addif} @var{address} @var{address}
2347 @item Darwin (MacOS/X)
2348 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2350 @tab @code{netsh interface ipv6 add address} @var{interface} @code{static} @var{address}/@var{prefixlength}
2354 @c ==================================================================
2358 In some cases it might be necessary to add more routes to the virtual network
2359 interface. There are two ways to indicate which interface a packet should go
2360 to, one is to use the name of the interface itself, another way is to specify
2361 the (local) address that is assigned to that interface (@var{local_address}). The
2362 former way is unambiguous and therefore preferable, but not all platforms
2365 Adding routes to IPv4 subnets:
2367 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2369 @tab @code{route add -net} @var{network_address} @code{netmask} @var{netmask} @var{interface}
2370 @item Linux iproute2
2371 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2373 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2375 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2377 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2379 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
2380 @item Darwin (MacOS/X)
2381 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2383 @tab @code{netsh routing ip add persistentroute} @var{network_address} @var{netmask} @var{interface} @var{local_address}
2386 Adding routes to IPv6 subnets:
2388 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2390 @tab @code{route add -A inet6} @var{network_address}@code{/}@var{prefixlength} @var{interface}
2391 @item Linux iproute2
2392 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2394 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2396 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
2398 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
2400 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
2401 @item Darwin (MacOS/X)
2404 @tab @code{netsh interface ipv6 add route} @var{network address}/@var{prefixlength} @var{interface}
2408 @c ==================================================================
2414 * Contact information::
2419 @c ==================================================================
2420 @node Contact information
2421 @section Contact information
2424 Tinc's website is at @url{http://www.tinc-vpn.org/},
2425 this server is located in the Netherlands.
2428 We have an IRC channel on the FreeNode and OFTC IRC networks. Connect to
2429 @uref{http://www.freenode.net/, irc.freenode.net}
2431 @uref{http://www.oftc.net/, irc.oftc.net}
2432 and join channel #tinc.
2435 @c ==================================================================
2440 @item Ivo Timmermans (zarq) (@email{ivo@@tinc-vpn.org})
2441 @item Guus Sliepen (guus) (@email{guus@@tinc-vpn.org})
2444 We have received a lot of valuable input from users. With their help,
2445 tinc has become the flexible and robust tool that it is today. We have
2446 composed a list of contributions, in the file called @file{THANKS} in
2447 the source distribution.
2450 @c ==================================================================
2452 @unnumbered Concept Index
2454 @c ==================================================================
2458 @c ==================================================================