\input texinfo @c -*-texinfo-*-
-@c $Id: tinc.texi,v 1.8.4.10 2000/12/05 08:54:22 zarq Exp $
+@c $Id: tinc.texi,v 1.8.4.18 2001/05/25 12:45:37 guus Exp $
@c %**start of header
@setfilename tinc.info
@settitle tinc Manual
This is the info manual for tinc, a Virtual Private Network daemon.
-Copyright @copyright{} 1998,199,2000 Ivo Timmermans
+Copyright @copyright{} 1998-2001 Ivo Timmermans
<itimmermans@@bigfoot.com>, Guus Sliepen <guus@@sliepen.warande.net> and
Wessel Dankers <wsl@@nl.linux.org>.
-$Id: tinc.texi,v 1.8.4.10 2000/12/05 08:54:22 zarq Exp $
+$Id: tinc.texi,v 1.8.4.18 2001/05/25 12:45:37 guus Exp $
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
@page
@vskip 0pt plus 1filll
@cindex copyright
-Copyright @copyright{} 1998,1999,2000 Ivo Timmermans
+Copyright @copyright{} 1998-2001 Ivo Timmermans
<itimmermans@@bigfoot.com>, Guus Sliepen <guus@@sliepen.warande.net> and
Wessel Dankers <wsl@@nl.linux.org>.
-$Id: tinc.texi,v 1.8.4.10 2000/12/05 08:54:22 zarq Exp $
+$Id: tinc.texi,v 1.8.4.18 2001/05/25 12:45:37 guus Exp $
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
@menu
* Introduction:: Introduction
-* Installing tinc - preparations::
-* Installing tinc - installation::
-* Configuring tinc::
-* Running tinc::
-* Technical information::
-* About us::
+* Preparations::
+* Installation::
+* Configuration::
+* Running tinc::
+* Technical information::
+* About us::
* Concept Index:: All used terms explained
@end menu
@contents
@c ==================================================================
-@node Introduction, Installing tinc - preparations, Top, Top
+@node Introduction, Preparations, Top, Top
@chapter Introduction
@cindex tinc
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
@menu
* VPNs:: Virtual Private Networks in general
* tinc:: about tinc
-* Supported platforms::
+* Supported platforms::
@end menu
@c ==================================================================
more than just one way.
@cindex private
-Private networks can consist of a single stand-alone ethernet LAN. Or
+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
+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.
+computers on the other end of the Internet.
@cindex virtual
This problem can be solved by using @emph{virtual} networks. Virtual
-networks can live on top of other networks, but do not interfere with
-each other. Mostly, virtual networks appear like a singe LAN, even though
+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 singe 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.
+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.
-@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
-that flows over the network.
-
@c ==================================================================
@node tinc, Supported platforms, VPNs, Introduction
@section tinc
@cindex vpnd
-@cindex ethertap
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
+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 @samp{vpnd}.
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
+@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.
@node Supported platforms, , tinc, Introduction
@section Supported platforms
-tinc works on Linux, FreeBSD and Solaris. These are the three platforms
+@cindex platforms
+tinc has been verified to work under Linux, FreeBSD and Solaris, with
+various hardware architectures. These are the three platforms
that are supported by the universial TUN/TAP device driver, so if
support for other operating systems is added to this driver, perhaps
tinc will run on them as well. Without this driver, tinc will most
likely compile and run, but it will not be able to send or receive data
packets.
-For a more up to date list, please check the list on our website:
+@cindex release
+The official release only truly supports Linux.
+For an up to date list of supported platforms, please check the list on
+our website:
@uref{http://tinc.nl.linux.org/platforms.html}.
@c ==================================================================
@subsection Linux
+@cindex Linux
tinc was first written for Linux running on an intel x86 processor, so
this is the best supported platform. The protocol however, and actually
anything about tinc, has been rewritten to support random byte ordering
and arbitrary word length. So in theory it should run on other
-processors that Linux runs on. Take care however, we haven't been able
-to really test it yet. If you want to run tinc on another platform than
-x86, and want to tell us how it went, please do so.
+processors that Linux runs on. It has already been verified to run on
+alpha and sparc processors as well.
-tinc uses the ethertap device that is provided in the standard kernel
-since version 2.1.60, so anything above that (2.2.x, 2.3.x, and the
-2.4.0-testx (which is current at the time of this writing) kernel
-versions) is able to support tinc.
+tinc uses the ethertap device or the universal TUN/TAP driver. The former is provided in the standard kernel
+from version 2.1.60 up to 2.3.x, but has been replaced in favour of the TUN/TAP driver in kernel versions 2.4.0 and later.
@c ==================================================================
@subsection FreeBSD
+@cindex FreeBSD
tinc on FreeBSD relies on the universial TUN/TAP driver for its data
-acquisition from the kernel. Therefore, tinc suports the same platforms
+acquisition from the kernel. Therefore, tinc will work on the same platforms
as this driver. These are: FreeBSD 3.x, 4.x, 5.x.
@c ==================================================================
@subsection Solaris
+@cindex Solaris
tinc on Solaris relies on the universial TUN/TAP driver for its data
-acquisition from the kernel. Therefore, tinc suports the same platforms
+acquisition from the kernel. Therefore, tinc will work on the same platforms
as this driver. These are: Solaris, 2.1.x.
@c
@c ==================================================================
-@node Installing tinc - preparations, Installing tinc - installation, Introduction, Top
-@chapter Installing tinc: preparations
+@node Preparations, Installation, Introduction, Top
+@chapter Preparations
This chapter contains information on how to prepare your system to
support tinc.
@menu
-* Configuring the kernel::
-* Libraries::
+* Configuring the kernel::
+* Libraries::
@end menu
@c ==================================================================
-@node Configuring the kernel, Libraries, Installing tinc - preparations, Installing tinc - preparations
+@node Configuring the kernel, Libraries, Preparations, Preparations
@section Configuring the kernel
-If you are running Linux, chances are good that your kernel already
-supports all the devices that tinc needs for proper operation. For
-example, the standard kernel from Redhat Linux already has support for
-ethertap and netlink compiled in. Debian users can use the modconf
-utility to select the modules. If your Linux distribution supports this
-method of selecting devices, look out for something called `ethertap',
-and `netlink_dev'. You need both these devices.
-
-If you can install these devices in a similar manner, you may skip this
-section.
+@cindex RedHat
+@cindex Debian
+@cindex netlink_dev
+@cindex tun
+@cindex ethertap
+If you are running Linux, chances are good that your kernel already supports
+all the devices that tinc needs for proper operation. For example, the
+standard kernel from Redhat Linux already has support for ethertap and netlink
+compiled in. Debian users can use the modconf utility to select the modules.
+If your Linux distribution supports this method of selecting devices, look out
+for something called `ethertap', and `netlink_dev' if it is using a kernel
+version prior to 2.4.0. In that case you will need both these devices. If you
+are using kernel 2.4.0 or later, you need to select `tun'.
+
+@cindex Kernel-HOWTO
+If you can install these devices in a similar manner, you may skip this section.
+Otherwise, you will have to recompile the kernel in order to turn on the required features.
+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.
@menu
-* Configuration of the Linux kernel::
-* Configuration of the FreeBSD kernel::
-* Configuration of the Solaris kernel::
+* Configuration of Linux kernels 2.1.60 up to 2.4.0::
+* Configuration of Linux kernels 2.4.0 and higher::
+* Configuration of FreeBSD kernels::
+* Configuration of Solaris kernels::
@end menu
@c ==================================================================
-@node Configuration of the Linux kernel, Configuration of the FreeBSD kernel, Configuring the kernel, Configuring the kernel
-@subsection Configuring the Linux 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.
+@node Configuration of Linux kernels 2.1.60 up to 2.4.0, Configuration of Linux kernels 2.4.0 and higher, Configuring the kernel, Configuring the kernel
+@subsection Configuration of Linux kernels 2.1.60 up to 2.4.0
-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!
-
-Here are the options you have to turn on when configuring a new
-kernel.
-
-For kernel 2.2.x:
+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
+<M> Netlink device emulation
Network device support
-<*> Ethertap network tap
+<M> Ethertap network tap
+@end example
+
+If you want to run more than one instance of tinc or other programs that use
+the ethertap, you have to compile the ethertap driver as a module, otherwise
+you can also choose to compile it directly into the kernel.
+
+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}:
+
+@example
+alias char-major-36 netlink_dev
+alias tap0 ethertap
+options tap0 -o tap0 unit=0
+alias tap1 ethertap
+options tap1 -o tap1 unit=1
+...
+alias tap@emph{N} ethertap
+options tap@emph{N} -o tap@emph{N} unit=@emph{N}
@end example
-For kernel 2.3.x and 2.4.x:
+Add as much alias/options lines as necessary.
+
+
+@c ==================================================================
+@node Configuration of Linux kernels 2.4.0 and higher, Configuration of FreeBSD kernels, Configuration of Linux kernels 2.1.60 up to 2.4.0, Configuring the kernel
+@subsection Configuration of Linux kernels 2.4.0 and higher
+
+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
-<*> Universal TUN/TAP device driver support
+<M> Universal TUN/TAP device driver support
@end example
+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 have an early 2.4 kernel, you can choose both the TUN/TAP driver and the
+`Ethertap network tap' device. This latter is marked obsolete, and chances are
+that it won't even function correctly anymore. Make sure you select the
+universal TUN/TAP driver.
-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}.
+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
-If you have a 2.4 kernel, you can also choose to use the `Ethertap
-network tap' device. This is marked obsolete, because the universal
-TUN/TAP driver is a newer implementation that is supposed to be used in
-favor of ethertap. For tinc, it doesn't really matter which one you
-choose; based on the device file name, tinc will make the right choice
-about what protocol to use.
-
-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 Configuration of the FreeBSD kernel, Configuration of the Solaris kernel, Configuration of the Linux kernel, Configuring the kernel
-@subsection Configuring the FreeBSD kernel
+@node Configuration of FreeBSD kernels, Configuration of Solaris kernels, Configuration of Linux kernels 2.4.0 and higher, Configuring the kernel
+@subsection Configuration of FreeBSD kernels
This section will contain information on how to configure your FreeBSD
kernel to support the universal TUN/TAP device. For 5.0 and 4.1
@c ==================================================================
-@node Configuration of the Solaris kernel, , Configuration of the FreeBSD kernel, Configuring the kernel
-@subsection Configuring the Solaris kernel
+@node Configuration of Solaris kernels, , Configuration of FreeBSD kernels, Configuring the kernel
+@subsection Configuration of Solaris kernels
This section will contain information on how to configure your Solaris
kernel to support the universal TUN/TAP device. You need to install
@c ==================================================================
-@node Libraries, , Configuring the kernel, Installing tinc - preparations
+@node Libraries, , Configuring the kernel, Preparations
@section Libraries
@cindex requirements
+@cindex libraries
Before you can configure or build tinc, you need to have the OpenSSL
library installed on your system. If you try to configure tinc without
having installed it, configure will give you an error message, and stop.
@menu
-* OpenSSL::
+* OpenSSL::
@end menu
@cindex OpenSSL
For all cryptography-related functions, tinc uses the functions provided
-by the OpenSSL library. We recommend using version 0.9.5 or 0.9.6 of
-this library. Other versions may also work, but we can guarantee
-nothing.
+by the OpenSSL library.
If this library is not installed, you wil get an error when configuring
tinc for build. Support for running tinc without having OpenSSL
@subsubheading License
+@cindex license
Since the license under which OpenSSL is distributed is not directly
compatible with the terms of the GNU GPL
@uref{http://www.openssl.org/support/faq.html#LEGAL2}, therefore we
@c
@c ==================================================================
-@node Installing tinc - installation, Configuring tinc, Installing tinc - preparations, Top
-@chapter Installing tinc: installation
+@node Installation, Configuration, Preparations, Top
+@chapter Installation
If you use Redhat or Debian, you may want to install one of the
precompiled packages for your system. These packages are equipped with
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.
@menu
-* Building tinc::
-* System files::
-* Interfaces::
+* Building and installing tinc::
+* System files::
@end menu
@c ==================================================================
-@node Building tinc, System files, Installing tinc - installation, Installing tinc - installation
-@section Building tinc
+@node Building and installing tinc, System files, Installation, Installation
+@section Building and installing tinc
+
+Detailed instructions on configuring the source, building tinc and installing tinc
+can be found in the file called @file{INSTALL}.
-Detailed instructions on configuring the source and building tinc can be
-found in the file called @file{INSTALL}.
+@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.
@c ==================================================================
-@node System files, Interfaces, Building tinc, Installing tinc - installation
+@node System files, , Building and installing tinc, Installation
@section System files
Before you can run tinc, you must make sure you have all the needed
files on your system.
@menu
-* Device files::
-* Other files::
+* Device files::
+* Other files::
@end menu
@node Device files, Other files, System files, System files
@subsection Device files
+@cindex device files
First, you'll need the special device file(s) that form the interface
between the kernel and the daemon.
eavesdropping would become a bit too easy. This does, however, imply
that you'd have to run tincd as root.
-If you use the universal TUN/TAP driver, you have to create the
-following device files (unless they already exist):
+If you use Linux and have a kernel version prior to 2.4.0, you have to make the
+ethertap devices:
@example
-mknod -m 600 /dev/... c .. ..
-chown 0.0 /dev/...
+mknod -m 600 /dev/tap0 c 36 16
+chown 0.0 /dev/tap0
+mknod -m 600 /dev/tap1 c 36 17
+chown 0.0 /dev/tap0
+...
+mknod -m 600 /dev/tap@emph{N} c 36 @emph{N+16}
+chown 0.0 /dev/tap@emph{N}
@end example
-If you want to have more devices, the device numbers will be .. .. ...
-
-If you use Linux, and you run the new 2.4 kernel using the devfs
-filesystem, then the tap device will be automatically generated as
-@file{/dev/netlink/tap0}.
+There is a maximum of 16 ethertap devices.
-If you use Linux and have kernel 2.2.x, you have to make the ethertap
-devices:
+If you use the universal TUN/TAP driver, you have to create the
+following device file (unless it already exist):
@example
-mknod -m 600 /dev/tap0 c 36 16
-chown 0.0 /dev/tap0
+mknod -m 600 /dev/tun c 10 200
+chown 0.0 /dev/tun
@end example
-Any further ethertap devices have minor device number 16 through 31.
+If you use Linux, and you run the new 2.4 kernel using the devfs filesystem,
+then the TUN/TAP device will probably be automatically generated as
+@file{/dev/net/tun}.
+
+Unlike the ethertap device, you do not need multiple device files if
+you are planning to run multiple tinc daemons.
@c ==================================================================
myvpn 10.0.0.0
@end example
-This has nothing to do with the MyVPNIP configuration variable that will be
-discussed later, it is only to make the output of the route command more
-legible.
-
@subsubheading @file{/etc/services}
+@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.
@end example
-@c ==================================================================
-@node Interfaces, , System files, Installing tinc - installation
-@section Interfaces
-
-Before you can start transmitting data over the tinc tunnel, you must
-set up the ethertap network devices.
-
-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.
-
-The actual setup of the ethertap device is quite simple, just repeat
-after me:
-
-@example
-ifconfig tap@emph{n} hw ether fe:fd:00:00:00:00
-@end example
-
-@cindex MAC address
-@cindex hardware address
-@strong{Note:} Since version 1.0pre3, all interface addresses are set to
-this address, whereas previous versions required the MAC to match the
-actual IP address.
-
-@cindex ifconfig
-To activate the device, you have to assign an IP address to it. To set
-an IP address @emph{IP} with network mask @emph{mask}, do the following:
-
-@example
-ifconfig tap@emph{n} @emph{xx}.@emph{xx}.@emph{xx}.@emph{xx} netmask @emph{mask}
-@end example
-
-@cindex netmask
-The netmask is the mask of the @emph{entire} VPN network, not just your
-own subnet. It is the same netmask you will have to specify with the
-VpnMask configuration variable.
-
-
@c
@c
@c
@c ==================================================================
-@node Configuring tinc, Running tinc, Installing tinc - installation, Top
-@chapter Configuring tinc
+@node Configuration, Running tinc, Installation, Top
+@chapter Configuration
@menu
-* Multiple networks::
-* How connections work::
-* Configuration file::
-* Example::
+* Configuration introduction::
+* Multiple networks::
+* How connections work::
+* Configuration files::
+* Generating keypairs::
+* Network interfaces::
+* Example configuration::
@end menu
@c ==================================================================
-@node Multiple networks, How connections work, Configuring tinc, Configuring tinc
-@section Multiple networks
+@node Configuration introduction, Multiple networks, Configuration, Configuration
+@section Configuration introduction
+
+@cindex Network Administrators Guide
+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?
+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.
+A good resource on networking is the
+@uref{http://www.linuxdoc.org/LDP/nag2/, Linux Network Administrators Guide}.
+
+If you have everything clearly pictured in your mind,
+proceed in the following order:
+First, generate the configuration files (tinc.conf, your host configuration file, tinc-up and perhaps tinc-down).
+Then generate the keypairs.
+Finally, distribute the host configuration files.
+These steps are described in the subsections below.
-@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 Multiple networks, How connections work, Configuration introduction, Configuration
+@section Multiple networks
+
+@cindex multiple networks
+@cindex netname
+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 ``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 sites of your VPN,
+but it is recommended that you choose one anyway.
-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.
+We will asume you use a netname throughout this document.
+This means that you call tincd with the -n argument,
+which will assign a netname to this daemon.
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 ``tinc.nn''.
+``root'' to /etc/tinc/netname/, where netname is your argument to the -n
+option. You'll notice that it appears in syslog as ``tinc.netname''.
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/tinc.conf,
-and the passphrases are now expected to be in /etc/tinc/passphrases/.
+/etc/tinc/netname/; the configuration file should be /etc/tinc/tinc.conf,
+and the host configuration files are now expected to be in /etc/tinc/hosts/.
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
@c ==================================================================
-@node How connections work, Configuration file, Multiple networks, Configuring tinc
+@node How connections work, Configuration files, Multiple networks, Configuration
@section How connections work
-Before going on, first a bit on how tinc sees connections.
-
-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.
+When tinc starts up, it parses the command-line options and then
+reads in the configuration file.
+If it sees a `ConnectTo' value pointing to another tinc daemon in the file,
+it will try to connect to that other one.
+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 any 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 eachother however.
@c ==================================================================
-@node Configuration file, Example, How connections work, Configuring tinc
-@section Configuration file
+@node Configuration files, Generating keypairs, How connections work, Configuration
+@section Configuration files
The actual configuration of the daemon is done in the file
-@file{/etc/tinc/nn/tinc.conf}.
+@file{/etc/tinc/netname/tinc.conf} and at least one other file in the directory
+@file{/etc/tinc/netname/hosts/}.
-This file consists of comments (lines started with a #) or assignments
+These file consists of comments (lines started with a #) or assignments
in the form of
@example
out, remember to replace it with at least one space character.
In this section all valid variables are listed in alphabetical order.
-The default value is given between parentheses; required directives are
-given in @strong{bold}.
+The default value is given between parentheses,
+other comments are between square brackets and
+required directives are given in @strong{bold}.
@menu
-* Main configuration variables::
-* Host configuration variables::
-* How to configure::
+* Main configuration variables::
+* Host configuration variables::
+* How to configure::
@end menu
@c ==================================================================
-@node Main configuration variables, Host configuration variables, Configuration file, Configuration file
+@node Main configuration variables, Host configuration variables, Configuration files, Configuration files
@subsection Main configuration variables
@table @asis
@item @strong{ConnectTo = <name>}
+@cindex ConnectTo
Specifies which host to connect to on startup. Multiple ConnectTo
variables may be specified, if connecting to the first one fails then
tinc will try the next one, and so on. It is possible to specify
instead just listen for incoming connections.
@item Hostnames = <yes|no> (no)
+@cindex Hostnames
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
configuration file.
@item Interface = <device>
+@cindex Interface
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.
@item InterfaceIP = <local address>
+@cindex InterfaceIP
If your computer has more than one IP address on a single interface (for
example if you are running virtual hosts), tinc will by default listen
on all of them for incoming connections. It is possible to bind tinc to
address.
@item KeyExpire = <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 KeyExpire
+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.
@item @strong{Name = <name>}
-This is a symbolic name for this connection. It can be anything
+@cindex Name
+This is a symbolic name for this connection. It can be anything
-@item PingTimeout = <seconds> (5)
+@item PingTimeout = <seconds> (60)
+@cindex PingTimeout
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.
-@item @strong{PrivateKey = <path>}
+@item PrivateKey = <key> [obsolete]
+@cindex PrivateKey
+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.
+
+@item @strong{PrivateKeyFile = <path>} [recommended]
+@cindex PrivateKeyFile
This is the full path name of the RSA private key file that was
generated by ``tincd --generate-keys''. It must be a full path, not a
-relative directory. (NOTE: In version 1.0pre3, this variable was used
-to give the key inline. This is no longer supported.)
+relative directory.
-@item TapDevice = <device> (/dev/tap0)
+@item @strong{TapDevice = <device>} (/dev/tap0 or /dev/net/tun)
+@cindex TapDevice
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.
-@item VpnMask = <mask>
-The mask that defines the scope of the entire VPN. This option is not
-used by the tinc daemon itself, but can be used by startup scripts to
-configure the ethertap devices correctly.
@end table
@c ==================================================================
-@node Host configuration variables, How to configure, Main configuration variables, Configuration file
+@node Host configuration variables, How to configure, Main configuration variables, Configuration files
@subsection Host configuration variables
@table @asis
-@item @strong{Address = <IP address|hostname>}
+@item @strong{Address = <IP address|hostname>} [recommended]
+@cindex Address
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.
-@item IndirectData = <yes|no> (no)
+@item IndirectData = <yes|no> (no) [experimental]
+@cindex IndirectData
This option specifies whether other tinc daemons besides the one you
specified with ConnectTo can make a direct connection to you. This is
especially useful if you are behind a firewall and it is impossible to
is best to leave this option out or set it to no.
@item Port = <port> (655)
+@cindex 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) o hexadecimal (prefixed with 0x). port is the port
number for both the UDP and the TCP (meta) connections.
-@item PublicKey = <path>
+@item PublicKey = <key> [obsolete]
+@cindex PublicKey
+This is the RSA public key for this host.
+
+@item PublicKeyFile = <path> [obsolete]
+@cindex PublicKeyFile
This is the full path name of the RSA public key file that was generated
by ``tincd --generate-keys''. It must be a full path, not a relative
-directory. (NOTE: In version 1.0pre3, this variable was used to give
-the key inline. This is no longer supported.)
+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.
@item Subnet = <IP address/maskbits>
+@cindex Subnet
This is the subnet range of all IP addresses that will be accepted by
-the host that defines it. Please be careful that no two subnets
-overlap. Every host @strong{must} have a different range of IP
-addresses that it can handle, otherwise you will see messages like
-`packet comes back to us'.
+the host that defines it.
-The range must contain the IP address of the tap device, not the real IP
-address of the host running tincd.
+The range must be contained in the IP address range of the tap device,
+not the real IP address of the host running tincd.
+@cindex CIDR notation
maskbits 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.
+/22. This conforms to standard CIDR notation as described in
+@uref{ftp://ftp.isi.edu/in-notes/rfc1519.txt, RFC1519}
-@item TCPonly = <yes|no> (no)
+@item TCPonly = <yes|no> (no) [experimental]
+@cindex TCPonly
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. @emph{This is
-experimental code, try this at your own risk.}
+firewall, or if UDP packet routing is disabled somehow. This is
+experimental code, try this at your own risk. It may not work at all.
+Setting this options also implicitly sets IndirectData.
@end table
@c ==================================================================
-@node How to configure, , Host configuration variables, Configuration file
+@node How to configure, , Host configuration variables, Configuration files
@subsection How to configure
-@subsubheading Step 1. Creating the key files
+@subsubheading Step 1. Creating the main configuration file
-For each host, you have to create a pair of RSA keys. One key is your
-private key, which is only known to you. The other one is the public
-key, which you should copy to all hosts wanting to authenticate to you.
+The main configuration file will be called @file{/etc/tinc/netname/tinc.conf}.
+Adapt the following example to create a basic configuration file:
+@example
+Name = @emph{yourname}
+TapDevice = @emph{/dev/tap0}
+PrivateKeyFile = /etc/tinc/@emph{netname}/rsa_key.priv
+@end example
-@subsubheading Step 2. Configuring each host
+Then, if you know to which other tinc daemon(s) yours is going to connect,
+add `ConnectTo' values.
-For every host in the VPN, you have to create two files. First there is
-the main configuration file, @file{/etc/tinc/vpn-name/tinc.conf}. In
-this file there should at least be three directives:
+@subsubheading Step 2. Creating your host configuration file
-@table @samp
-@item Name
-You should fill in the name of this host (or rather, the name of this
-leaf of the VPN). It can be called after the hostname, the physical
-location, the department, or the name of one of your boss' pets. It can
-be anything, as long as all these names are unique across the entire
-VPN.
-
-@item PrivateKey
-Fill in the full pathname to the file that contains the private RSA key.
-
-@item ConnectTo
-This is the name of the host that you want to connect to (not a DNS
-name, rather the name that is given with the Name parameter in that
-hosts tinc.conf). This is the upstream connection. If your computer is
-a central node, you might want to leave this out to make it stay idle
-until someone connects to it.
-@end table
+If you added a line containing `Name = yourname' in the main configuarion file,
+you will need to create a host configuration file @file{/etc/tinc/netname/hosts/yourname}.
+Adapt the following example to create a host configuration file:
-@cindex host configuration file
-Then you should create a file with the name you gave yourself in
-tinc.conf (the `Name' parameter), located in
-@file{/etc/tinc/vpn-name/hosts/}. In this file, which we call the
-`@emph{host configuration file}', only one variable is required:
+@example
+Address = @emph{your.real.hostname.org}
+Subnet = @emph{192.168.1.0/24}
+@end example
-@table @samp
-@item Subnet
-The IP range that this host accepts as being `local'. All packets with
-a destination address that is within this subnet will be sent to us.
-@end table
+You can also use an IP address instead of a hostname.
+The `Subnet' specifies the address range that is local for @emph{your part of the VPN only}.
+If you have multiple address ranges you can specify more than one `Subnet'.
+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).
-@subsubheading Step 3. Bringing it all together
+@c ==================================================================
+@node Generating keypairs, Network interfaces, Configuration files, Configuration
+@section Generating keypairs
+
+@cindex key generation
+Now that you have already created the main configuration file and your host configuration file,
+you can easily create a public/private keypair by entering the following command:
-Now for all hosts that you want to create a direct connection to, -- you
-connect to them or they connect to you -- you get a copy of their host
-configuration file and their public RSA key.
+@example
+tincd -n @emph{netname} -K
+@end example
-For each host configuration file, you add two variables:
+tinc will generate a public and a private key and ask you where to put them.
+Just press enter to accept the defaults.
-@table @samp
-@item Address
-Enter the IP address or DNS hostname for this host. This is only needed
-if you connect to this host.
-@item PublicKey
-Put the full pathname to this hosts public RSA key here.
-@end table
+@c ==================================================================
+@node Network interfaces, Example configuration, Generating keypairs, Configuration
+@section Network interfaces
+
+Before tinc can start transmitting data over the tunnel, it must
+set up the ethertap network devices.
+
+First, decide which IP addresses you want to have associated with these
+devices, and what network mask they must have.
+
+tinc will open an ethertap device or TUN/TAP device, which will also
+create a network interface called `tap0', or `tap1', and so on if you are using
+the ethertap driver, or a network interface with the same name as netname
+if you are using the universal TUN/TAP driver.
-When you did this, you should be ready to create your first connection.
-Pay attention to the system log, most errors will only be visible
-there. If you get an error, you can check @ref{Error messages}.
+@cindex tinc-up
+You can configure that device by putting ordinary ifconfig, route, and other commands
+to a script named @file{/etc/tinc/netname/tinc-up}. When tinc starts, this script
+will be executed. When tinc exits, it will execute the script named
+@file{/etc/tinc/netname/tinc-down}, but normally you don't need to create that script.
+
+An example @file{tinc-up} script when using the TUN/TAP driver:
+
+@example
+#!/bin/sh
+ifconfig $NETNAME hw ether fe:fd:00:00:00:00
+ifconfig $NETNAME @emph{xx}.@emph{xx}.@emph{xx}.@emph{xx} netmask @emph{mask}
+ifconfig $NETNAME -arp
+@end example
+
+@cindex MAC address
+@cindex hardware address
+The first line sets up the MAC address of the network interface.
+Due to the nature of how Ethernet and tinc work, it has to be set to fe:fd:00:00:00:00.
+(tinc versions prior to 1.0pre3 required that the MAC address matched the IP address.)
+You can use the environment variable $NETNAME to get the name of the interface.
+If you are using the ethertap driver however, you need to replace it with tap@emph{N},
+corresponding to the device file name.
+
+@cindex ifconfig
+The next line gives the interface an IP address and a netmask.
+The kernel will also automatically add a 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.
+
+@cindex arp
+The last line tells the kernel not to use ARP on that interface.
+Again this has to do with how Ethernet and tinc work. Don't forget to add this line.
@c ==================================================================
-@node Example, , Configuration file, Configuring tinc
-@section Example
+@node Example configuration, , Network interfaces, Configuration
+@section Example configuration
@cindex 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.
+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.
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
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
+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.
+how these example host is set up. All branches use the netname `company'
+for this particular VPN.
+
+@subsubheading For Branch A
-@subsubheading For A
+@emph{BranchA} would be configured like this:
-@emph{A} would be configured like this:
+In @file{/etc/tinc/company/tinc-up}:
@example
-#ifconfig eth0 10.1.54.1 netmask 255.255.0.0 broadcast 10.1.255.255
+# Real interface of internal network:
+# ifconfig eth0 10.1.54.1 netmask 255.255.0.0 broadcast 10.1.255.255
+
ifconfig tap0 hw ether fe:fd:00:00:00:00
ifconfig tap0 10.1.54.1 netmask 255.0.0.0
+ifconfig tap0 -arp
@end example
-and in /etc/tinc/tinc.conf:
+and in @file{/etc/tinc/company/tinc.conf}:
@example
-Name = A
-PrivateKey = /etc/tinc/A.priv
-VpnMask = 255.0.0.0
+Name = BranchA
+PrivateKey = /etc/tinc/company/rsa_key.priv
+TapDevice = /dev/tap0
@end example
-On all hosts, /etc/tinc/hosts/A contains:
+On all hosts, /etc/tinc/company/hosts/BranchA contains:
@example
Subnet = 10.1.0.0/16
Address = 1.2.3.4
-PublicKey = /etc/tinc/hosts/A.pub
+
+Note that the IP addresses of eth0 and tap0 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 give both real internal network interfaces and tap interfaces the same IP address,
+since that will make things a lot easier to remember and set up.
+
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
@end example
-@subsubheading For B
+@subsubheading For Branch B
+
+In @file{/etc/tinc/company/tinc-up}:
@example
-#ifconfig eth0 10.2.43.8 netmask 255.255.0.0 broadcast 10.2.255.255
+# Real interface of internal network:
+# ifconfig eth0 10.2.43.8 netmask 255.255.0.0 broadcast 10.2.255.255
+
ifconfig tap0 hw ether fe:fd:00:00:00:00
ifconfig tap0 10.2.1.12 netmask 255.0.0.0
+ifconfig tap0 -arp
@end example
-and in /etc/tinc/tinc.conf:
+and in @file{/etc/tinc/company/tinc.conf}:
@example
-Name = B
-ConnectTo = A
-PrivateKey = /etc/tinc/B.priv
-VpnMask = 255.0.0.0
+Name = BranchB
+ConnectTo = BranchA
+PrivateKey = /etc/tinc/company/rsa_key.priv
@end example
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.
-On all hosts, /etc/tinc/hosts/B:
+On all hosts, in @file{/etc/tinc/company/hosts/BranchB}:
@example
Subnet = 10.2.0.0/16
Address = 2.3.4.5
-PublicKey = /etc/tinc/hosts/B.pub
+
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
@end example
-@subsubheading For C
+@subsubheading For Branch C
+
+In @file{/etc/tinc/company/tinc-up}:
@example
-#ifconfig eth0 10.3.69.254 netmask 255.255.0.0 broadcast 10.3.255.255
-ifconfig tap0 hw ether fe:fd:00:00:00:00
-ifconfig tap0 10.3.69.254 netmask 255.0.0.0
+# Real interface of internal network:
+# ifconfig eth0 10.3.69.254 netmask 255.255.0.0 broadcast 10.3.255.255
+
+ifconfig tap1 hw ether fe:fd:00:00:00:00
+ifconfig tap1 10.3.69.254 netmask 255.0.0.0
+ifconfig tap1 -arp
@end example
-and in /etc/tinc/A/tinc.conf:
+and in @file{/etc/tinc/company/tinc.conf}:
@example
-Name = C
-ConnectTo = A
+Name = BranchC
+ConnectTo = BranchA
TapDevice = /dev/tap1
-VpnMask = 255.0.0.0
@end example
C already has another daemon that runs on port 655, so they have to
-reserve another port for tinc. It can connect to other tinc daemons on
-the regular port though, so no ConnectPort variable is needed. They
-also use the netname to distinguish between the two. tinc is started
-with `tincd -n A'.
+reserve another port for tinc. It knows the portnumber it has to listen on
+from it's own host configuration file.
-On all hosts, /etc/tinc/hosts/C:
+On all hosts, in @file{/etc/tinc/company/hosts/BranchC}:
@example
+Address = 3.4.5.6
Subnet = 10.3.0.0/16
Port = 2000
-PublicKey = /etc/tinc/hosts/C.pub
+
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
@end example
-@subsubheading For D
+@subsubheading For Branch D
+
+In @file{/etc/tinc/company/tinc-up}:
@example
-#ifconfig tap0 10.4.3.32 netmask 255.255.0.0 broadcast 10.4.255.255
-ifconfig tap0 hw ether fe:fd:0a:04:03:20
-ifconfig tap0 10.4.3.32 netmask 255.0.0.0
+# Real interface of internal network:
+# ifconfig eth0 10.4.3.32 netmask 255.255.0.0 broadcast 10.4.255.255
+
+ifconfig company hw ether fe:fd:0a:04:03:20
+ifconfig company 10.4.3.32 netmask 255.0.0.0
+ifconfig company -arp
@end example
-and in /etc/tinc/tinc.conf:
+and in @file{/etc/tinc/company/tinc.conf}:
@example
-MyVirtualIP = 10.4.3.32/16
-ConnectTo = 3.4.5.6
-ConnectPort = 2000
-VpnMask=255.0.0.0
+Name = BranchD
+ConnectTo = BranchC
+TapDevice = /dev/net/tun
+PrivateKeyFile = /etc/tinc/company/rsa_key.priv
@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, but it doesn't need
-to have a different ListenPort.
+port 2000. It knows the port number from the host configuration file.
+Also note that since D uses the TUN/TAP driver, the network interface
+will not be called `tun' or `tap0' or something like that, but will
+have the same name as netname.
-@subsubheading Key files
-
-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.
+On all hosts, in @file{/etc/tinc/company/hosts/BranchD}:
-A stores a copy of B's passphrase in /etc/tinc/passphrases/10.2.1.12
+@example
+Subnet = 10.4.0.0/16
+Address = 4.5.6.7
-A stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.69.254
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
+@end example
-B stores a copy of A's passphrase in /etc/tinc/passphrases/10.1.54.1
+@subsubheading Key files
-C stores a copy of A's passphrase in /etc/tinc/A/passphrases/10.1.54.1
+A, B, C and D all have generated a public/private keypair with the following command:
-C stores a copy of D's passphrase in /etc/tinc/A/passphrases/10.4.3.32
+@example
+tincd -n company -K
+@end example
-D stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.69.254
+The private key is stored in @file{/etc/tinc/company/rsa_key.priv},
+the public key is put into the host configuration file in the @file{/etc/tinc/company/hosts/} directory.
+During key generation, tinc automatically guesses the right filenames based on the -n option and
+the Name directive in the @file{tinc.conf} file (if it is available).
@subsubheading Starting
-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.
-
+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, Technical information, Configuring tinc, Top
+@node Running tinc, Technical information, Configuration, 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.
-
-@menu
-* Managing keys::
-* Runtime options::
-* Error messages::
-@end menu
-
+If everything else is done, you can start tinc by typing the following command:
-@c ==================================================================
-@node Managing keys, Runtime options, Running tinc, Running tinc
-@section Managing keys
-
-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.
-
-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).
-
-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.
-
-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.
-
-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}.
+@example
+tincd -n @emph{netname}
+@end example
-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.
+@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.
-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.
+@menu
+* Runtime options::
+* Error messages::
+@end menu
@c ==================================================================
-@node Runtime options, Error messages, Managing keys, Running tinc
+@node Runtime options, Error messages, , Running tinc
@section Runtime options
Besides the settings in the configuration file, tinc also accepts some
@cindex options
@c from the manpage
@table @samp
-@item -c, --config=FILE
-Read configuration options from FILE. The default is
-@file{/etc/tinc/nn/tinc.conf}.
+@item -c, --config=PATH
+Read configuration options from the directory PATH. The default is
+@file{/etc/tinc/netname/}.
+@cindex debug level
@item -d
Increase debug level. The higher it gets, the more gets
logged. Everything goes via syslog.
@item -n, --net=NETNAME
Connect to net NETNAME. @xref{Multiple networks}.
-@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.
+@item -K, --generate-keys[=BITS]
+Generate public/private keypair of BITS length. If BITS is not specified,
+1024 is the default. 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
+in combination with -K). After that, tinc will quit.
@item --help
Display a short reminder of these runtime options and terminate.
@table @strong
@item Could not open /dev/tap0: No such device
-@table @bullet
-@item You forgot to insmod netlink_dev.o
-@item You forgot to compile `Netlink device emulation' in the kernel
-@end table
-@item Can't write to tun/tap device: No such device
-@table @bullet
-@item You forgot to insmod tun.o
-@item You forgot to compile `Universal TUN/TAP driver' in the kernel
-@end table
+@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.
+@end itemize
@item Packet with destination 1.2.3.4 is looping back to us!
-@table @bullet
-@item Some host has an IP address range that overlaps with yours
-Different hosts must have different IP ranges (as given with Subnet in
-the host configuration files). tinc relies on this information to route
-its data, so each IP address range must have exactly one host
-associated. You will only see this message if you specified a debug
+
+@itemize
+@item Something is not configured right. Packets are being sent out to the
+tap 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 netmask which is
+just as large as the netmask of the tap device. 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!
-@end table
+@item Chances are that a `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 Network doesn't work, syslog shows only packets of length 46
+
+@cindex arp
+@example
+Jan 1 12:00:00 host tinc.net[1234]: Read packet of length 46 from tap device
+Jan 1 12:00:00 host tinc.net[1234]: Trying to look up 0.0.192.168 in connection list failed!
+@end example
+@itemize
+@item Add the `ifconfig $NETNAME -arp' to tinc-up.
+@end itemize
@item Network address and subnet mask do not match!
-@table @bullet
-@item The Subnet field must contain a network address
-If you only want to use one IP address, set the netmask to /32.
-@end table
+
+@itemize
+@item The Subnet field must contain a @emph{network} address.
+@item If you only want to use one IP address, set the netmask to /32.
+@end itemize
@item This is a bug: net.c:253: 24: Some error
-@table @bullet
-@item This is something that should not have happened
+
+@itemize
+@item This is something that should not have happened.
Please report this, and tell us exactly what went wrong before you got
this message. In normal operation, these errors should not occur.
-@end table
+@end itemize
@item Error reading RSA key file `rsa_key.priv': No such file or directory
-@table @bullet
-@item You must specify the complete pathname
+
+@itemize
+@item You must specify the complete pathname.
Specifying a relative path does not make sense here. tinc changes its
directory to / when starting (to avoid keeping a mount point busy); and
even if we built in a default directory to look for these files, the key
files are bound to be in a different directory.
-@end table
-
-@item Error reading RSA key file `fd47...8ceb': No such file or directory
-@table @bullet
-@item You specified the key here, not a pathname
-In version 1.0pre3, you had to put your key here. This has changed, the
-keys are now stored in separate files. This means you have to
-regenerate these keys.
-@end table
+@end itemize
@end table
-
-
@c ==================================================================
@node Technical information, About us, Running tinc, Top
@chapter Technical information
+
@menu
-* The Connection::
-* Security::
+* The connection::
+* The meta-protocol::
+* Security::
@end menu
@c ==================================================================
-@node The Connection, Security, Technical information, Technical information
-@section The basic philosophy of the way tinc works
-@cindex connection
+@node The connection, The meta-protocol, Technical information, Technical information
+@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
-* Protocol Preview::
-* The Meta-connection::
+* The UDP tunnel::
+* The meta-connection::
@end menu
@c ==================================================================
-@node Protocol Preview, The Meta-connection, The Connection, The Connection
-@subsection A preview of the way the tinc works
+@node The UDP tunnel, The meta-connection, The connection, The connection
+@subsection The UDP tunnel
@cindex ethertap
@cindex frame type
@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,
+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
+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
+frames, because it needs IP headers for routing.
+Plans to support other protocols and switching instead of routing are being made.
+(Some code for IPv6 routing and switching is already present but nonfunctional.)
+When tinc knows
which type of frame it has read, it can also read the source and
destination address from it.
encryption algorithm available is blowfish.
@cindex encapsulating
+@cindex UDP
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
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.
+To let the kernel on the receiving end accept the packet, the destination MAC
+address must match that of the tap interface. Because of the routing nature
+of tinc, ARP is not possible. tinc solves this by always overwriting the
+destination MAC address with fe:fd:0:0:0:0. That is also the reason why you must
+set the MAC address of your tap interface to that address.
+
@c ==================================================================
-@node The Meta-connection, , Protocol Preview, The Connection
+@node The meta-connection, , The UDP tunnel, The connection
@subsection The meta-connection
Having only an 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.
+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.
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 ACK's sent instead of just one. Furthermore, if 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 resending packets.
+start re-sending packets.
+
@c ==================================================================
-@node Security, , The Connection, Technical information
+@node The meta-protocol, Security, The connection, Technical information
+@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 and to read and write requests by hand, provided that one
+understands the numeric codes sent.
+
+The authentication scheme is described in @ref{Authentication protocol}. After a
+succesful 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_HOST
+@cindex ADD_SUBNET
+@example
+daemon message
+--------------------------------------------------------------------------
+origin ADD_HOST daemon a329e18c:655 0
+ | | +--> options
+ | +---------> real address:port
+ +-------------------> name of new tinc daemon
+origin ADD_SUBNET daemon 1,0a010100/ffffff00
+ | | | +--> netmask
+ | | +----------> vpn IPv4 network address
+ | +----------------> subnet type (1=IPv4)
+ +--------------------> owner of this subnet
+--------------------------------------------------------------------------
+@end example
+
+@cindex DEL_HOST
+@cindex DEL_SUBNET
+In case daemons leave the VPN, DEL_HOST and DEL_SUBNET messages with exactly
+the same syntax are sent to inform the other daemons of the departure.
+
+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. If any hop on the way has already learned the key, it will
+act as a proxy and forward it's copy back to the requestor.
+
+@cindex REQ_KEY
+@cindex ANS_KEY
+@cindex KEY_CHANGED
+@example
+daemon message
+--------------------------------------------------------------------------
+daemon REQ_KEY origin destination
+ | +--> name of the tinc daemon it wants the key from
+ +----------> name of the daemon that wants the key
+daemon ANS_KEY origin destination e4ae0b0a82d6e0078179b5290c62c7d0
+ | | \______________________________/
+ | | +--> 128 bits key
+ | +--> name of the daemon that wants the key
+ +----------> name of the daemon that uses this key
+daemon KEY_CHANGED origin
+ +--> daemon that has changed it's packet key
+--------------------------------------------------------------------------
+@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.
+
+@cindex PING
+@cindex PONG
+@example
+daemon message
+--------------------------------------------------------------------------
+origin PING 9e76
+ \__/
+ +--> 2 bytes of salt (random data)
+dest. PONG 3b8d
+ \__/
+ +--> 2 bytes of salt (random data)
+--------------------------------------------------------------------------
+@end example
+
+This basically covers what is sent over the meta connection by
+tinc.
+
+
+@c ==================================================================
+@node Security, , The meta-protocol, Technical information
@section About tinc's encryption and other security-related issues.
-@cindex tinc
+@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
+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.
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.
+tinc uses blowfish encryption in CBC mode and a small amount of salt
+at the beginning of each packet to make sure eavesdroppers cannot get
+any information at all from the packets they can intercept.
@menu
-* Key Types::
-* Key Management::
-* Authentication::
+* Authentication protocol::
+* Encryption of network packets::
@end menu
-@c ==================================================================
-@node Key Types, Key Management, Security, Security
-@subsection Key Types
-@c FIXME: check if I'm not talking nonsense
-
-There are several types of encryption keys. Tinc uses two of them,
-symmetric private keypairs and public/private keypairs.
-
-Public/private keypairs are used in public key cryptography. It enables
-someone to send out a public key with which other people can encrypt their
-data. The encrypted data now can only be decrypted by the person who has
-the private key that matches the public key. So, a public key only allows
-@emph{other} people to send encrypted messages to you. This is very useful
-in setting up private communications channels. Just send out your public key
-and other people can talk to you in a secure way. But how can you know
-the other person is who she says she is?
-
-For authentication itself tinc uses symmetric private keypairs, referred
-to as a passphrase. The identity of each tinc daemon is defined by it's
-passphrase (like you can be identified by your social security number).
-Every tinc daemon that is allowed to connect to you has a copy of your
-passphrase (hence symmetrical).
-
-It would also be possible to use public/private keypairs for authentication,
-so that you could shout out your public key and don't need to keep it
-secret (like the passphrase you would have to send to someone else). Also,
-no one else has to know a private key from you.
-Both forms have their pros and cons, and at the moment tinc just uses passphrases
-(which are computationaly more efficient and perhaps in some way more
-secure).
@c ==================================================================
-@node Key Management, Authentication, Key Types, Security
-@subsection Key Management
-@c FIXME change for the current protocol
+@node Authentication protocol, Encryption of network packets, Security, Security
+@subsection Authentication protocol
-@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 authentication
+A new scheme for authentication in tinc has been devised, which offers some
+improvements over the protocol used in 1.0pre2 and 1.0pre3. Explanation is
+below.
-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.
+@example
+daemon message
+--------------------------------------------------------------------------
+client <attempts connection>
+
+server <accepts connection>
+
+client ID client 10 0
+ | | +-> options
+ | +---> version
+ +--------> name of tinc daemon
+
+server ID server 10 0
+ | | +-> options
+ | +---> version
+ +--------> name of tinc daemon
+
+client META_KEY 5f0823a93e35b69e...7086ec7866ce582b
+ \_________________________________/
+ +-> RSAKEYLEN bits totally random string S1,
+ encrypted with server's public RSA key
+
+server META_KEY 6ab9c1640388f8f0...45d1a07f8a672630
+ \_________________________________/
+ +-> RSAKEYLEN bits totally random string S2,
+ encrypted with client's public RSA key
+
+From now on:
+ - the client will encrypt outgoing traffic using S1
+ - the server will encrypt outgoing traffic using S2
+
+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
+--------------------------------------------------------------------------
+@end example
-@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.
+This new scheme has several improvements, both in efficiency and security.
+
+First of all, the server sends exactly the same kind of messages over the wire
+as the client. The previous versions of tinc first authenticated the client,
+and then the server. This scheme even allows both sides to send their messages
+simultaneously, there is no need to wait for the other to send something first.
+This means that any calculations that need to be done upon sending or receiving
+a message can also be done in parallel. This is especially important when doing
+RSA encryption/decryption. Given that these calculations are the main part of
+the CPU time spent for the authentication, speed is improved by a factor 2.
+
+Second, only one RSA encrypted message is sent instead of two. This reduces the
+amount of information attackers can see (and thus use for a cryptographic
+attack). It also improves speed by a factor two, making the total speedup a
+factor 4.
+
+Third, and most important:
+The symmetric cipher keys are exchanged first, the challenge is done
+afterwards. In the previous authentication scheme, because a man-in-the-middle
+could pass the challenge/chal_reply phase (by just copying the messages between
+the two real tinc daemons), but no information was exchanged that was really
+needed to read the rest of the messages, the challenge/chal_reply phase was of
+no real use. The man-in-the-middle was only stopped by the fact that only after
+the ACK messages were encrypted with the symmetric cipher. Potentially, it
+could even send it's own symmetric key to the server (if it knew the server's
+public key) and read some of the metadata the server would send it (it was
+impossible for the mitm to read actual network packets though). The new scheme
+however prevents this.
+
+This new scheme makes sure that first of all, symmetric keys are exchanged. The
+rest of the messages are then encrypted with the symmetric cipher. Then, each
+side can only read received messages if they have their private key. The
+challenge is there to let the other side know that the private key is really
+known, because a challenge reply can only be sent back if the challenge is
+decrypted correctly, and that can only be done with knowledge of the private
+key.
+
+Fourth: the first thing that is send via the symmetric cipher encrypted
+connection is a totally random string, so that there is no known plaintext (for
+an attacker) in the beginning of the encrypted stream.
-Both parties then calculate g^ab mod p = k. k is the new, shared, but
-still secret key.
-To obtain a key k of a sufficient length (128 bits in our vpnd), p
-should be 2^129-1 or more.
+@c ==================================================================
+@node Encryption of network packets, , Authentication protocol, Security
+@subsection Encryption of network packet
+@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 retreive it. The packet is stored in a queue while waiting for the
+key to arrive.
-@c ==================================================================
-@node Authentication, , Key Management, Security
-@subsection Authentication
-@c FIXME: recheck
-
-@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.
-
-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.
-B will never receive the real passphrase though, because it was
-encrypted using public/private keypairs. This way there is no way an
-imposter could steal A's passphrase.
-
-@cindex passphrase
-@c ehrmz... but we only use 1024 bits passphrases ourselves? [guus]
-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.
-
-These passphrases could be stored in a file that is non-readable by
-anyone else but root; e.g. @file{/etc/tinc/passphrases} with UID 0
-and permissions mode 700.
-
-The only thing that needs to be taken care of is how A can securely send
-a copy of it's passphrase to B if B doesn't have it yet. This could be
-done via mail with PGP, but you should be really convinced of the
-identity of the person who owns the email address you are sending this to.
-Swapping floppy disks in real life might be the best way to do this!
+@cindex UDP
+The UDP packet containing the network packet from the VPN has the following layout:
+
+@example
+... | IP header | UDP header | salt | VPN packet | UDP trailer
+ \___________________/
+ |
+ V
+ Encrypted with symmetric cipher
+@end example
+
+So, the entire UDP payload is encrypted using a symmetric cipher (blowfish in CBC mode).
+2 bytes of salt (random data) are added in front of the actual VPN packet,
+so that two VPN packets with (almost) the same content do not seem to be
+the same for eavesdroppers.
+2 bytes of salt may not seem much, but you can encrypt 65536 identical packets
+now without an attacker being able to see that they were identical.
+Given a MTU of 1500 this means 96 Megabyte of data.
+
+There is no @emph{extra} provision against replay attacks or alteration of packets.
+However, the VPN packets, normally UDP or TCP packets themselves, contain
+checksums and sequence numbers.
+Since those checksums and sequence numbers are encrypted,
+they automatically become @emph{cryptographically secure}.
+The kernel will handle any checksum errors and duplicate packets.
@c ==================================================================
@menu
-* Contact Information::
-* Authors::
+* Contact Information::
+* Authors::
@end menu
@node Contact Information, Authors, About us, About us
@section Contact information
-tinc's main page is at @url{http://tinc.nl.linux.org/},
+@cindex website
+tinc's website is at @url{http://tinc.nl.linux.org/},
this server is located in the Netherlands.
+@cindex IRC
We have an IRC channel on the Open Projects IRC network. Connect to
@uref{http://openprojects.nu/services/irc.html, irc.openprojects.net},
and join channel #tinc.
@item Ivo Timmermans (zarq) (@email{itimmermans@@bigfoot.com})
Main coder/hacker and maintainer of the package.
-@item Guus Sliepen (guus)
+@item Guus Sliepen (guus) (@email{guus@@sliepen.warande.net})
Originator of it all, co-author.
-@item Wessel Dankers (Ubiq)
-General obfuscater of the code.
+@item Wessel Dankers (Ubiq) (@email{wsl@@nl.linux.org})
+For the name `tinc' and various suggestions.
@end table
@c ==================================================================
@contents
@bye
-
projects / tinc / blobdiff