1 \input texinfo @c -*-texinfo-*-
8 @include tincinclude.texi
11 @dircategory Networking tools
13 * tinc: (tinc). The tinc Manual.
16 This is the info manual for @value{PACKAGE} version @value{VERSION}, a Virtual Private Network daemon.
18 Copyright @copyright{} 1998-2009 Ivo Timmermans,
19 Guus Sliepen <guus@@tinc-vpn.org> and
20 Wessel Dankers <wsl@@tinc-vpn.org>.
22 Permission is granted to make and distribute verbatim copies of this
23 manual provided the copyright notice and this permission notice are
24 preserved on all copies.
26 Permission is granted to copy and distribute modified versions of this
27 manual under the conditions for verbatim copying, provided that the
28 entire resulting derived work is distributed under the terms of a
29 permission notice identical to this one.
35 @subtitle Setting up a Virtual Private Network with tinc
36 @author Ivo Timmermans and Guus Sliepen
39 @vskip 0pt plus 1filll
40 This is the info manual for @value{PACKAGE} version @value{VERSION}, a Virtual Private Network daemon.
42 Copyright @copyright{} 1998-2009 Ivo Timmermans,
43 Guus Sliepen <guus@@tinc-vpn.org> and
44 Wessel Dankers <wsl@@tinc-vpn.org>.
46 Permission is granted to make and distribute verbatim copies of this
47 manual provided the copyright notice and this permission notice are
48 preserved on all copies.
50 Permission is granted to copy and distribute modified versions of this
51 manual under the conditions for verbatim copying, provided that the
52 entire resulting derived work is distributed under the terms of a
53 permission notice identical to this one.
58 @c ==================================================================
68 * Technical information::
69 * Platform specific information::
71 * Concept Index:: All used terms explained
75 @c ==================================================================
80 Tinc is a Virtual Private Network (VPN) daemon that uses tunneling and
81 encryption to create a secure private network between hosts on the
84 Because the tunnel appears to the IP level network code as a normal
85 network device, there is no need to adapt any existing software.
86 The encrypted tunnels allows VPN sites to share information with each other
87 over the Internet without exposing any information to others.
89 This document is the manual for tinc. Included are chapters on how to
90 configure your computer to use tinc, as well as the configuration
91 process of tinc itself.
94 * Virtual Private Networks::
96 * Supported platforms::
99 @c ==================================================================
100 @node Virtual Private Networks
101 @section Virtual Private Networks
104 A Virtual Private Network or VPN is a network that can only be accessed
105 by a few elected computers that participate. This goal is achievable in
106 more than just one way.
109 Private networks can consist of a single stand-alone Ethernet LAN. Or
110 even two computers hooked up using a null-modem cable. In these cases,
112 obvious that the network is @emph{private}, no one can access it from the
113 outside. But if your computers are linked to the Internet, the network
114 is not private anymore, unless one uses firewalls to block all private
115 traffic. But then, there is no way to send private data to trusted
116 computers on the other end of the Internet.
119 This problem can be solved by using @emph{virtual} networks. Virtual
120 networks can live on top of other networks, but they use encapsulation to
121 keep using their private address space so they do not interfere with
122 the Internet. Mostly, virtual networks appear like a singe LAN, even though
123 they can span the entire world. But virtual networks can't be secured
124 by using firewalls, because the traffic that flows through it has to go
125 through the Internet, where other people can look at it.
127 As is the case with either type of VPN, anybody could eavesdrop. Or
128 worse, alter data. Hence it's probably advisable to encrypt the data
129 that flows over the network.
131 When one introduces encryption, we can form a true VPN. Other people may
132 see encrypted traffic, but if they don't know how to decipher it (they
133 need to know the key for that), they cannot read the information that flows
134 through the VPN. This is what tinc was made for.
137 @c ==================================================================
142 I really don't quite remember what got us started, but it must have been
143 Guus' idea. He wrote a simple implementation (about 50 lines of C) that
144 used the ethertap device that Linux knows of since somewhere
145 about kernel 2.1.60. It didn't work immediately and he improved it a
146 bit. At this stage, the project was still simply called "vpnd".
148 Since then, a lot has changed---to say the least.
151 Tinc now supports encryption, it consists of a single daemon (tincd) for
152 both the receiving and sending end, it has become largely
153 runtime-configurable---in short, it has become a full-fledged
154 professional package.
156 @cindex traditional VPNs
158 Tinc also allows more than two sites to connect to eachother and form a single VPN.
159 Traditionally VPNs are created by making tunnels, which only have two endpoints.
160 Larger VPNs with more sites are created by adding more tunnels.
161 Tinc takes another approach: only endpoints are specified,
162 the software itself will take care of creating the tunnels.
163 This allows for easier configuration and improved scalability.
165 A lot can---and will be---changed. We have a number of things that we would like to
166 see in the future releases of tinc. Not everything will be available in
167 the near future. Our first objective is to make tinc work perfectly as
168 it stands, and then add more advanced features.
170 Meanwhile, we're always open-minded towards new ideas. And we're
174 @c ==================================================================
175 @node Supported platforms
176 @section Supported platforms
179 Tinc has been verified to work under Linux, FreeBSD, OpenBSD, NetBSD, MacOS/X (Darwin), Solaris, and Windows (both natively and in a Cygwin environment),
180 with various hardware architectures. These are some of the platforms
181 that are supported by the universal tun/tap device driver or other virtual network device drivers.
182 Without such a driver, tinc will most
183 likely compile and run, but it will not be able to send or receive data
187 For an up to date list of supported platforms, please check the list on
189 @uref{http://www.tinc-vpn.org/platforms}.
197 @c Preparing your system
204 @c ==================================================================
206 @chapter Preparations
208 This chapter contains information on how to prepare your system to
212 * Configuring the kernel::
217 @c ==================================================================
218 @node Configuring the kernel
219 @section Configuring the kernel
222 * Configuration of Linux kernels::
223 * Configuration of FreeBSD kernels::
224 * Configuration of OpenBSD kernels::
225 * Configuration of NetBSD kernels::
226 * Configuration of Solaris kernels::
227 * Configuration of Darwin (MacOS/X) kernels::
228 * Configuration of Windows::
232 @c ==================================================================
233 @node Configuration of Linux kernels
234 @subsection Configuration of Linux kernels
236 @cindex Universal tun/tap
237 For tinc to work, you need a kernel that supports the Universal tun/tap device.
238 Most distributions come with kernels that already support this.
239 Here are the options you have to turn on when configuring a new kernel:
242 Code maturity level options
243 [*] Prompt for development and/or incomplete code/drivers
244 Network device support
245 <M> Universal tun/tap device driver support
248 It's not necessary to compile this driver as a module, even if you are going to
249 run more than one instance of tinc.
251 If you decide to build the tun/tap driver as a kernel module, add these lines
252 to @file{/etc/modules.conf}:
255 alias char-major-10-200 tun
259 @c ==================================================================
260 @node Configuration of FreeBSD kernels
261 @subsection Configuration of FreeBSD kernels
263 For FreeBSD version 4.1 and higher, tun and tap drivers are included in the default kernel configuration.
264 Using tap devices is recommended.
267 @c ==================================================================
268 @node Configuration of OpenBSD kernels
269 @subsection Configuration of OpenBSD kernels
271 For OpenBSD version 2.9 and higher,
272 the tun driver is included in the default kernel configuration.
273 There is also a kernel patch from @uref{http://diehard.n-r-g.com/stuff/openbsd/}
274 which adds a tap device to OpenBSD which should work with tinc,
275 but with recent versions of OpenBSD,
276 a tun device can act as a tap device by setting the link0 option with ifconfig.
278 @c ==================================================================
279 @node Configuration of NetBSD kernels
280 @subsection Configuration of NetBSD kernels
282 For NetBSD version 1.5.2 and higher,
283 the tun driver is included in the default kernel configuration.
285 Tunneling IPv6 may not work on NetBSD's tun device.
288 @c ==================================================================
289 @node Configuration of Solaris kernels
290 @subsection Configuration of Solaris kernels
292 For Solaris 8 (SunOS 5.8) and higher,
293 the tun driver may or may not be included in the default kernel configuration.
294 If it isn't, the source can be downloaded from @uref{http://vtun.sourceforge.net/tun/}.
295 For x86 and sparc64 architectures, precompiled versions can be found at @uref{http://www.monkey.org/~dugsong/fragroute/}.
296 If the @file{net/if_tun.h} header file is missing, install it from the source package.
299 @c ==================================================================
300 @node Configuration of Darwin (MacOS/X) kernels
301 @subsection Configuration of Darwin (MacOS/X) kernels
303 Tinc on Darwin relies on a tunnel driver for its data acquisition from the kernel.
304 Tinc supports either the driver from @uref{http://tuntaposx.sourceforge.net/},
305 which supports both tun and tap style devices,
306 and also the driver from from @uref{http://chrisp.de/en/projects/tunnel.html}.
307 The former driver is recommended.
308 The tunnel driver must be loaded before starting tinc with the following command:
315 @c ==================================================================
316 @node Configuration of Windows
317 @subsection Configuration of Windows
319 You will need to install the latest TAP-Win32 driver from OpenVPN.
320 You can download it from @uref{http://openvpn.sourceforge.net}.
321 Using the Network Connections control panel,
322 configure the TAP-Win32 network interface in the same way as you would do from the tinc-up script,
323 as explained in the rest of the documentation.
326 @c ==================================================================
332 Before you can configure or build tinc, you need to have the OpenSSL,
333 zlib and lzo libraries installed on your system. If you try to configure tinc without
334 having them installed, configure will give you an error message, and stop.
343 @c ==================================================================
348 For all cryptography-related functions, tinc uses the functions provided
349 by the OpenSSL library.
351 If this library is not installed, you wil get an error when configuring
352 tinc for build. Support for running tinc without having OpenSSL
353 installed @emph{may} be added in the future.
355 You can use your operating system's package manager to install this if
356 available. Make sure you install the development AND runtime versions
359 If you have to install OpenSSL manually, you can get the source code
360 from @url{http://www.openssl.org/}. Instructions on how to configure,
361 build and install this package are included within the package. Please
362 make sure you build development and runtime libraries (which is the
365 If you installed the OpenSSL libraries from source, it may be necessary
366 to let configure know where they are, by passing configure one of the
367 --with-openssl-* parameters.
370 --with-openssl=DIR OpenSSL library and headers prefix
371 --with-openssl-include=DIR OpenSSL headers directory
372 (Default is OPENSSL_DIR/include)
373 --with-openssl-lib=DIR OpenSSL library directory
374 (Default is OPENSSL_DIR/lib)
378 @subsubheading License
381 The complete source code of tinc is covered by the GNU GPL version 2.
382 Since the license under which OpenSSL is distributed is not directly
383 compatible with the terms of the GNU GPL
384 @uref{http://www.openssl.org/support/faq.html#LEGAL2}, we
385 include an exemption to the GPL (see also the file COPYING.README) to allow
386 everyone to create a statically or dynamically linked executable:
389 This program is released under the GPL with the additional exemption
390 that compiling, linking, and/or using OpenSSL is allowed. You may
391 provide binary packages linked to the OpenSSL libraries, provided that
392 all other requirements of the GPL are met.
395 Since the LZO library used by tinc is also covered by the GPL,
396 we also present the following exemption:
399 Hereby I grant a special exception to the tinc VPN project
400 (http://www.tinc-vpn.org/) to link the LZO library with the OpenSSL library
401 (http://www.openssl.org).
403 Markus F.X.J. Oberhumer
407 @c ==================================================================
412 For the optional compression of UDP packets, tinc uses the functions provided
415 If this library is not installed, you wil get an error when configuring
416 tinc for build. Support for running tinc without having zlib
417 installed @emph{may} be added in the future.
419 You can use your operating system's package manager to install this if
420 available. Make sure you install the development AND runtime versions
423 If you have to install zlib manually, you can get the source code
424 from @url{http://www.gzip.org/zlib/}. Instructions on how to configure,
425 build and install this package are included within the package. Please
426 make sure you build development and runtime libraries (which is the
430 @c ==================================================================
435 Another form of compression is offered using the lzo library.
437 If this library is not installed, you wil get an error when configuring
438 tinc for build. Support for running tinc without having lzo
439 installed @emph{may} be added in the future.
441 You can use your operating system's package manager to install this if
442 available. Make sure you install the development AND runtime versions
445 If you have to install lzo manually, you can get the source code
446 from @url{http://www.oberhumer.com/opensource/lzo/}. Instructions on how to configure,
447 build and install this package are included within the package. Please
448 make sure you build development and runtime libraries (which is the
461 @c ==================================================================
463 @chapter Installation
465 If you use Debian, you may want to install one of the
466 precompiled packages for your system. These packages are equipped with
467 system startup scripts and sample configurations.
469 If you cannot use one of the precompiled packages, or you want to compile tinc
470 for yourself, you can use the source. The source is distributed under
471 the GNU General Public License (GPL). Download the source from the
472 @uref{http://www.tinc-vpn.org/download, download page}, which has
473 the checksums of these files listed; you may wish to check these with
474 md5sum before continuing.
476 Tinc comes in a convenient autoconf/automake package, which you can just
477 treat the same as any other package. Which is just untar it, type
478 `./configure' and then `make'.
479 More detailed instructions are in the file @file{INSTALL}, which is
480 included in the source distribution.
483 * Building and installing tinc::
488 @c ==================================================================
489 @node Building and installing tinc
490 @section Building and installing tinc
492 Detailed instructions on configuring the source, building tinc and installing tinc
493 can be found in the file called @file{INSTALL}.
495 @cindex binary package
496 If you happen to have a binary package for tinc for your distribution,
497 you can use the package management tools of that distribution to install tinc.
498 The documentation that comes along with your distribution will tell you how to do that.
501 * Darwin (MacOS/X) build environment::
502 * Cygwin (Windows) build environment::
503 * MinGW (Windows) build environment::
507 @c ==================================================================
508 @node Darwin (MacOS/X) build environment
509 @subsection Darwin (MacOS/X) build environment
511 In order to build tinc on Darwin, you need to install the MacOS/X Developer Tools
512 from @uref{http://developer.apple.com/tools/macosxtools.html} and
513 a recent version of Fink from @uref{http://fink.sourceforge.net/}.
515 After installation use fink to download and install the following packages:
516 autoconf25, automake, dlcompat, m4, openssl, zlib and lzo.
518 @c ==================================================================
519 @node Cygwin (Windows) build environment
520 @subsection Cygwin (Windows) build environment
522 If Cygwin hasn't already been installed, install it directly from
523 @uref{http://www.cygwin.com/}.
525 When tinc is compiled in a Cygwin environment, it can only be run in this environment,
526 but all programs, including those started outside the Cygwin environment, will be able to use the VPN.
527 It will also support all features.
529 @c ==================================================================
530 @node MinGW (Windows) build environment
531 @subsection MinGW (Windows) build environment
533 You will need to install the MinGW environment from @uref{http://www.mingw.org}.
535 When tinc is compiled using MinGW it runs natively under Windows,
536 it is not necessary to keep MinGW installed.
538 When detaching, tinc will install itself as a service,
539 which will be restarted automatically after reboots.
542 @c ==================================================================
544 @section System files
546 Before you can run tinc, you must make sure you have all the needed
547 files on your system.
555 @c ==================================================================
557 @subsection Device files
560 Most operating systems nowadays come with the necessary device files by default,
561 or they have a mechanism to create them on demand.
563 If you use Linux and do not have udev installed,
564 you may need to create the following device file if it does not exist:
567 mknod -m 600 /dev/net/tun c 10 200
571 @c ==================================================================
573 @subsection Other files
575 @subsubheading @file{/etc/networks}
577 You may add a line to @file{/etc/networks} so that your VPN will get a
578 symbolic name. For example:
584 @subsubheading @file{/etc/services}
587 You may add this line to @file{/etc/services}. The effect is that you
588 may supply a @samp{tinc} as a valid port number to some programs. The
589 number 655 is registered with the IANA.
594 # Ivo Timmermans <ivo@@tinc-vpn.org>
609 @c ==================================================================
611 @chapter Configuration
614 * Configuration introduction::
615 * Multiple networks::
616 * How connections work::
617 * Configuration files::
618 * Generating keypairs::
619 * Network interfaces::
620 * Example configuration::
623 @c ==================================================================
624 @node Configuration introduction
625 @section Configuration introduction
627 Before actually starting to configure tinc and editing files,
628 make sure you have read this entire section so you know what to expect.
629 Then, make it clear to yourself how you want to organize your VPN:
630 What are the nodes (computers running tinc)?
631 What IP addresses/subnets do they have?
632 What is the network mask of the entire VPN?
633 Do you need special firewall rules?
634 Do you have to set up masquerading or forwarding rules?
635 Do you want to run tinc in router mode or switch mode?
636 These questions can only be answered by yourself,
637 you will not find the answers in this documentation.
638 Make sure you have an adequate understanding of networks in general.
639 @cindex Network Administrators Guide
640 A good resource on networking is the
641 @uref{http://www.linuxdoc.org/LDP/nag2/, Linux Network Administrators Guide}.
643 If you have everything clearly pictured in your mind,
644 proceed in the following order:
645 First, generate the configuration files (@file{tinc.conf}, your host configuration file, @file{tinc-up} and perhaps @file{tinc-down}).
646 Then generate the keypairs.
647 Finally, distribute the host configuration files.
648 These steps are described in the subsections below.
651 @c ==================================================================
652 @node Multiple networks
653 @section Multiple networks
655 @cindex multiple networks
657 In order to allow you to run more than one tinc daemon on one computer,
658 for instance if your computer is part of more than one VPN,
659 you can assign a @var{netname} to your VPN.
660 It is not required if you only run one tinc daemon,
661 it doesn't even have to be the same on all the sites of your VPN,
662 but it is recommended that you choose one anyway.
664 We will asume you use a netname throughout this document.
665 This means that you call tincd with the -n argument,
666 which will assign a netname to this daemon.
668 The effect of this is that the daemon will set its configuration
669 root to @file{@value{sysconfdir}/tinc/@var{netname}/}, where @var{netname} is your argument to the -n
670 option. You'll notice that it appears in syslog as @file{tinc.@var{netname}}.
672 However, it is not strictly necessary that you call tinc with the -n
673 option. In this case, the network name would just be empty, and it will
674 be used as such. tinc now looks for files in @file{@value{sysconfdir}/tinc/}, instead of
675 @file{@value{sysconfdir}/tinc/@var{netname}/}; the configuration file should be @file{@value{sysconfdir}/tinc/tinc.conf},
676 and the host configuration files are now expected to be in @file{@value{sysconfdir}/tinc/hosts/}.
678 But it is highly recommended that you use this feature of tinc, because
679 it will be so much clearer whom your daemon talks to. Hence, we will
680 assume that you use it.
683 @c ==================================================================
684 @node How connections work
685 @section How connections work
687 When tinc starts up, it parses the command-line options and then
688 reads in the configuration file tinc.conf.
689 If it sees one or more `ConnectTo' values pointing to other tinc daemons in that file,
690 it will try to connect to those other daemons.
691 Whether this succeeds or not and whether `ConnectTo' is specified or not,
692 tinc will listen for incoming connection from other deamons.
693 If you did specify a `ConnectTo' value and the other side is not responding,
694 tinc will keep retrying.
695 This means that once started, tinc will stay running until you tell it to stop,
696 and failures to connect to other tinc daemons will not stop your tinc daemon
697 for trying again later.
698 This means you don't have to intervene if there are temporary network problems.
702 There is no real distinction between a server and a client in tinc.
703 If you wish, you can view a tinc daemon without a `ConnectTo' value as a server,
704 and one which does specify such a value as a client.
705 It does not matter if two tinc daemons have a `ConnectTo' value pointing to each other however.
708 @c ==================================================================
709 @node Configuration files
710 @section Configuration files
712 The actual configuration of the daemon is done in the file
713 @file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf} and at least one other file in the directory
714 @file{@value{sysconfdir}/tinc/@var{netname}/hosts/}.
716 These file consists of comments (lines started with a #) or assignments
723 The variable names are case insensitive, and any spaces, tabs, newlines
724 and carriage returns are ignored. Note: it is not required that you put
725 in the `=' sign, but doing so improves readability. If you leave it
726 out, remember to replace it with at least one space character.
728 In this section all valid variables are listed in alphabetical order.
729 The default value is given between parentheses,
730 other comments are between square brackets.
733 * Main configuration variables::
734 * Host configuration variables::
740 @c ==================================================================
741 @node Main configuration variables
742 @subsection Main configuration variables
745 @cindex AddressFamily
746 @item AddressFamily = <ipv4|ipv6|any> (any)
747 This option affects the address family of listening and outgoing sockets.
748 If any is selected, then depending on the operating system
749 both IPv4 and IPv6 or just IPv6 listening sockets will be created.
751 @cindex BindToAddress
752 @item BindToAddress = <@var{address}> [experimental]
753 If your computer has more than one IPv4 or IPv6 address, tinc
754 will by default listen on all of them for incoming connections.
755 It is possible to bind only to a single address with this variable.
757 This option may not work on all platforms.
759 @cindex BindToInterface
760 @item BindToInterface = <@var{interface}> [experimental]
761 If you have more than one network interface in your computer, tinc will
762 by default listen on all of them for incoming connections. It is
763 possible to bind tinc to a single interface like eth0 or ppp0 with this
766 This option may not work on all platforms.
769 @item ConnectTo = <@var{name}>
770 Specifies which other tinc daemon to connect to on startup.
771 Multiple ConnectTo variables may be specified,
772 in which case outgoing connections to each specified tinc daemon are made.
773 The names should be known to this tinc daemon
774 (i.e., there should be a host configuration file for the name on the ConnectTo line).
776 If you don't specify a host with ConnectTo,
777 tinc won't try to connect to other daemons at all,
778 and will instead just listen for incoming connections.
781 @item Device = <@var{device}> (@file{/dev/tap0}, @file{/dev/net/tun} or other depending on platform)
782 The virtual network device to use.
783 Tinc will automatically detect what kind of device it is.
784 Note that you can only use one device per daemon.
785 Under Windows, use @var{Interface} instead of @var{Device}.
786 Note that you can only use one device per daemon.
787 See also @ref{Device files}.
790 @item DeviceType = <tun|tunnohead|tunifhead|tap> (only supported on BSD platforms)
791 The type of the virtual network device.
792 Tinc will normally automatically select the right type, and this option should not be used.
793 However, in case tinc does not seem to correctly interpret packets received from the virtual network device,
794 using this option might help.
799 Depending on the platform, this can either be with or without an address family header (see below).
803 Set type to tun without an address family header.
804 Tinc will expect packets read from the virtual network device to start with an IP header.
805 On some platforms IPv6 packets cannot be read from or written to the device in this mode.
809 Set type to tun with an address family header.
810 Tinc will expect packets read from the virtual network device
811 to start with a four byte header containing the address family,
812 followed by an IP header.
813 This mode should support both IPv4 and IPv6 packets.
817 Tinc will expect packets read from the virtual network device
818 to start with an Ethernet header.
821 @cindex GraphDumpFile
822 @item GraphDumpFile = <@var{filename}> [experimental]
823 If this option is present,
824 tinc will dump the current network graph to the file @var{filename}
825 every minute, unless there were no changes to the graph.
826 The file is in a format that can be read by graphviz tools.
827 If @var{filename} starts with a pipe symbol |,
828 then the rest of the filename is interpreted as a shell command
829 that is executed, the graph is then sent to stdin.
832 @item Hostnames = <yes|no> (no)
833 This option selects whether IP addresses (both real and on the VPN)
834 should be resolved. Since DNS lookups are blocking, it might affect
835 tinc's efficiency, even stopping the daemon for a few seconds everytime
836 it does a lookup if your DNS server is not responding.
838 This does not affect resolving hostnames to IP addresses from the
842 @item Interface = <@var{interface}>
843 Defines the name of the interface corresponding to the virtual network device.
844 Depending on the operating system and the type of device this may or may not actually set the name of the interface.
845 Under Windows, this variable is used to select which network interface will be used.
846 If you specified a Device, this variable is almost always already correctly set.
849 @item Mode = <router|switch|hub> (router)
850 This option selects the way packets are routed to other daemons.
856 variables in the host configuration files will be used to form a routing table.
857 Only unicast packets of routable protocols (IPv4 and IPv6) are supported in this mode.
859 This is the default mode, and unless you really know you need another mode, don't change it.
863 In this mode the MAC addresses of the packets on the VPN will be used to
864 dynamically create a routing table just like an Ethernet switch does.
865 Unicast, multicast and broadcast packets of every protocol that runs over Ethernet are supported in this mode
866 at the cost of frequent broadcast ARP requests and routing table updates.
868 This mode is primarily useful if you want to bridge Ethernet segments.
872 This mode is almost the same as the switch mode, but instead
873 every packet will be broadcast to the other daemons
874 while no routing table is managed.
878 @item KeyExpire = <@var{seconds}> (3600)
879 This option controls the time the encryption keys used to encrypt the data
880 are valid. It is common practice to change keys at regular intervals to
881 make it even harder for crackers, even though it is thought to be nearly
882 impossible to crack a single key.
885 @item MACExpire = <@var{seconds}> (600)
886 This option controls the amount of time MAC addresses are kept before they are removed.
887 This only has effect when Mode is set to "switch".
890 @item Name = <@var{name}> [required]
891 This is a symbolic name for this connection.
892 The name should consist only of alfanumeric and underscore characters (a-z, A-Z, 0-9 and _).
895 @item PingInterval = <@var{seconds}> (60)
896 The number of seconds of inactivity that tinc will wait before sending a
897 probe to the other end.
900 @item PingTimeout = <@var{seconds}> (5)
901 The number of seconds to wait for a response to pings or to allow meta
902 connections to block. If the other end doesn't respond within this time,
903 the connection is terminated, and the others will be notified of this.
905 @cindex PriorityInheritance
906 @item PriorityInheritance = <yes|no> (no) [experimental]
907 When this option is enabled the value of the TOS field of tunneled IPv4 packets
908 will be inherited by the UDP packets that are sent out.
911 @item PrivateKey = <@var{key}> [obsolete]
912 This is the RSA private key for tinc. However, for safety reasons it is
913 advised to store private keys of any kind in separate files. This prevents
914 accidental eavesdropping if you are editting the configuration file.
916 @cindex PrivateKeyFile
917 @item PrivateKeyFile = <@var{path}> (@file{@value{sysconfdir}/tinc/@var{netname}/rsa_key.priv})
918 This is the full path name of the RSA private key file that was
919 generated by @samp{tincd --generate-keys}. It must be a full path, not a
922 Note that there must be exactly one of PrivateKey
924 specified in the configuration file.
926 @cindex ProcessPriority
927 @item ProcessPriority = <low|normal|high>
928 When this option is used the priority of the tincd process will be adjusted.
929 Increasing the priority may help to reduce latency and packet loss on the VPN.
932 @item TunnelServer = <yes|no> (no) [experimental]
933 When this option is enabled tinc will no longer forward information between other tinc daemons,
934 and will only allow nodes and subnets on the VPN which are present in the
935 @file{@value{sysconfdir}/tinc/@var{netname}/hosts/} directory.
940 @c ==================================================================
941 @node Host configuration variables
942 @subsection Host configuration variables
946 @item Address = <@var{IP address}|@var{hostname}> [recommended]
947 This variable is only required if you want to connect to this host. It
948 must resolve to the external IP address where the host can be reached,
949 not the one that is internal to the VPN.
952 @item Cipher = <@var{cipher}> (blowfish)
953 The symmetric cipher algorithm used to encrypt UDP packets.
954 Any cipher supported by OpenSSL is recognized.
955 Furthermore, specifying "none" will turn off packet encryption.
956 It is best to use only those ciphers which support CBC mode.
959 @item Compression = <@var{level}> (0)
960 This option sets the level of compression used for UDP packets.
961 Possible values are 0 (off), 1 (fast zlib) and any integer up to 9 (best zlib),
962 10 (fast lzo) and 11 (best lzo).
965 @item Digest = <@var{digest}> (sha1)
966 The digest algorithm used to authenticate UDP packets.
967 Any digest supported by OpenSSL is recognized.
968 Furthermore, specifying "none" will turn off packet authentication.
971 @item IndirectData = <yes|no> (no)
972 This option specifies whether other tinc daemons besides the one you
973 specified with ConnectTo can make a direct connection to you. This is
974 especially useful if you are behind a firewall and it is impossible to
975 make a connection from the outside to your tinc daemon. Otherwise, it
976 is best to leave this option out or set it to no.
979 @item MACLength = <@var{bytes}> (4)
980 The length of the message authentication code used to authenticate UDP packets.
981 Can be anything from 0
982 up to the length of the digest produced by the digest algorithm.
985 @item PMTU = <@var{mtu}> (1514)
986 This option controls the initial path MTU to this node.
988 @cindex PMTUDiscovery
989 @item PMTUDiscovery = <yes|no> (yes)
990 When this option is enabled, tinc will try to discover the path MTU to this node.
991 After the path MTU has been discovered, it will be enforced on the VPN.
994 @item Port = <@var{port}> (655)
995 This is the port this tinc daemon listens on.
996 You can use decimal portnumbers or symbolic names (as listed in @file{/etc/services}).
999 @item PublicKey = <@var{key}> [obsolete]
1000 This is the RSA public key for this host.
1002 @cindex PublicKeyFile
1003 @item PublicKeyFile = <@var{path}> [obsolete]
1004 This is the full path name of the RSA public key file that was generated
1005 by @samp{tincd --generate-keys}. It must be a full path, not a relative
1009 From version 1.0pre4 on tinc will store the public key directly into the
1010 host configuration file in PEM format, the above two options then are not
1011 necessary. Either the PEM format is used, or exactly
1012 @strong{one of the above two options} must be specified
1013 in each host configuration file, if you want to be able to establish a
1014 connection with that host.
1017 @item Subnet = <@var{address}[/@var{prefixlength}[#@var{weight}]]>
1018 The subnet which this tinc daemon will serve.
1019 Tinc tries to look up which other daemon it should send a packet to by searching the appropiate subnet.
1020 If the packet matches a subnet,
1021 it will be sent to the daemon who has this subnet in his host configuration file.
1022 Multiple subnet lines can be specified for each daemon.
1024 Subnets can either be single MAC, IPv4 or IPv6 addresses,
1025 in which case a subnet consisting of only that single address is assumed,
1026 or they can be a IPv4 or IPv6 network address with a prefixlength.
1027 Shorthand notations are not supported.
1028 For example, IPv4 subnets must be in a form like 192.168.1.0/24,
1029 where 192.168.1.0 is the network address and 24 is the number of bits set in the netmask.
1030 Note that subnets like 192.168.1.1/24 are invalid!
1031 Read a networking HOWTO/FAQ/guide if you don't understand this.
1032 IPv6 subnets are notated like fec0:0:0:1:0:0:0:0/64.
1033 MAC addresses are notated like 0:1a:2b:3c:4d:5e.
1035 @cindex CIDR notation
1036 Prefixlength is the number of bits set to 1 in the netmask part; for
1037 example: netmask 255.255.255.0 would become /24, 255.255.252.0 becomes
1038 /22. This conforms to standard CIDR notation as described in
1039 @uref{ftp://ftp.isi.edu/in-notes/rfc1519.txt, RFC1519}
1041 A Subnet can be given a weight to indicate its priority over identical Subnets
1042 owned by different nodes. The default weight is 10. Lower values indicate
1043 higher priority. Packets will be sent to the node with the highest priority,
1044 unless that node is not reachable, in which case the node with the next highest
1045 priority will be tried, and so on.
1048 @item TCPonly = <yes|no> (no)
1049 If this variable is set to yes, then the packets are tunnelled over a
1050 TCP connection instead of a UDP connection. This is especially useful
1051 for those who want to run a tinc daemon from behind a masquerading
1052 firewall, or if UDP packet routing is disabled somehow.
1053 Setting this options also implicitly sets IndirectData.
1057 @c ==================================================================
1062 Apart from reading the server and host configuration files,
1063 tinc can also run scripts at certain moments.
1064 Under Windows (not Cygwin), the scripts should have the extension .bat.
1068 @item @value{sysconfdir}/tinc/@var{netname}/tinc-up
1069 This is the most important script.
1070 If it is present it will be executed right after the tinc daemon has been
1071 started and has connected to the virtual network device.
1072 It should be used to set up the corresponding network interface,
1073 but can also be used to start other things.
1074 Under Windows you can use the Network Connections control panel instead of creating this script.
1077 @item @value{sysconfdir}/tinc/@var{netname}/tinc-down
1078 This script is started right before the tinc daemon quits.
1080 @item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-up
1081 This script is started when the tinc daemon with name @var{host} becomes reachable.
1083 @item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-down
1084 This script is started when the tinc daemon with name @var{host} becomes unreachable.
1086 @item @value{sysconfdir}/tinc/@var{netname}/host-up
1087 This script is started when any host becomes reachable.
1089 @item @value{sysconfdir}/tinc/@var{netname}/host-down
1090 This script is started when any host becomes unreachable.
1092 @item @value{sysconfdir}/tinc/@var{netname}/subnet-up
1093 This script is started when a Subnet becomes reachable.
1094 The Subnet and the node it belongs to are passed in environment variables.
1096 @item @value{sysconfdir}/tinc/@var{netname}/subnet-down
1097 This script is started when a Subnet becomes unreachable.
1100 @cindex environment variables
1101 The scripts are started without command line arguments,
1102 but can make use of certain environment variables.
1103 Under UNIX like operating systems the names of environment variables must be preceded by a $ in scripts.
1104 Under Windows, in @file{.bat} files, they have to be put between % signs.
1109 If a netname was specified, this environment variable contains it.
1113 Contains the name of this tinc daemon.
1117 Contains the name of the virtual network device that tinc uses.
1121 Contains the name of the virtual network interface that tinc uses.
1122 This should be used for commands like ifconfig.
1126 When a host becomes (un)reachable, this is set to its name.
1127 If a subnet becomes (un)reachable, this is set to the owner of that subnet.
1129 @cindex REMOTEADDRESS
1131 When a host becomes (un)reachable, this is set to its real address.
1135 When a host becomes (un)reachable,
1136 this is set to the port number it uses for communication with other tinc daemons.
1140 When a subnet becomes (un)reachable, this is set to the subnet.
1145 @c ==================================================================
1146 @node How to configure
1147 @subsection How to configure
1149 @subsubheading Step 1. Creating the main configuration file
1151 The main configuration file will be called @file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf}.
1152 Adapt the following example to create a basic configuration file:
1155 Name = @var{yourname}
1156 Device = @file{/dev/tap0}
1159 Then, if you know to which other tinc daemon(s) yours is going to connect,
1160 add `ConnectTo' values.
1162 @subsubheading Step 2. Creating your host configuration file
1164 If you added a line containing `Name = yourname' in the main configuarion file,
1165 you will need to create a host configuration file @file{@value{sysconfdir}/tinc/@var{netname}/hosts/yourname}.
1166 Adapt the following example to create a host configuration file:
1169 Address = your.real.hostname.org
1170 Subnet = 192.168.1.0/24
1173 You can also use an IP address instead of a hostname.
1174 The `Subnet' specifies the address range that is local for @emph{your part of the VPN only}.
1175 If you have multiple address ranges you can specify more than one `Subnet'.
1176 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).
1179 @c ==================================================================
1180 @node Generating keypairs
1181 @section Generating keypairs
1183 @cindex key generation
1184 Now that you have already created the main configuration file and your host configuration file,
1185 you can easily create a public/private keypair by entering the following command:
1188 tincd -n @var{netname} -K
1191 Tinc will generate a public and a private key and ask you where to put them.
1192 Just press enter to accept the defaults.
1195 @c ==================================================================
1196 @node Network interfaces
1197 @section Network interfaces
1199 Before tinc can start transmitting data over the tunnel, it must
1200 set up the virtual network interface.
1202 First, decide which IP addresses you want to have associated with these
1203 devices, and what network mask they must have.
1205 Tinc will open a virtual network device (@file{/dev/tun}, @file{/dev/tap0} or similar),
1206 which will also create a network interface called something like @samp{tun0}, @samp{tap0}.
1207 If you are using the Linux tun/tap driver, the network interface will by default have the same name as the @var{netname}.
1208 Under Windows you can change the name of the network interface from the Network Connections control panel.
1211 You can configure the network interface by putting ordinary ifconfig, route, and other commands
1212 to a script named @file{@value{sysconfdir}/tinc/@var{netname}/tinc-up}.
1213 When tinc starts, this script will be executed. When tinc exits, it will execute the script named
1214 @file{@value{sysconfdir}/tinc/@var{netname}/tinc-down}, but normally you don't need to create that script.
1216 An example @file{tinc-up} script:
1220 ifconfig $INTERFACE 192.168.1.1 netmask 255.255.0.0
1223 This script gives the interface an IP address and a netmask.
1224 The kernel will also automatically add a route to this interface, so normally you don't need
1225 to add route commands to the @file{tinc-up} script.
1226 The kernel will also bring the interface up after this command.
1228 The netmask is the mask of the @emph{entire} VPN network, not just your
1231 The exact syntax of the ifconfig and route commands differs from platform to platform.
1232 You can look up the commands for setting addresses and adding routes in @ref{Platform specific information},
1233 but it is best to consult the manpages of those utilities on your platform.
1236 @c ==================================================================
1237 @node Example configuration
1238 @section Example configuration
1242 Imagine the following situation. Branch A of our example `company' wants to connect
1243 three branch offices in B, C and D using the Internet. All four offices
1244 have a 24/7 connection to the Internet.
1246 A is going to serve as the center of the network. B and C will connect
1247 to A, and D will connect to C. Each office will be assigned their own IP
1251 A: net 10.1.0.0 mask 255.255.0.0 gateway 10.1.54.1 internet IP 1.2.3.4
1252 B: net 10.2.0.0 mask 255.255.0.0 gateway 10.2.1.12 internet IP 2.3.4.5
1253 C: net 10.3.0.0 mask 255.255.0.0 gateway 10.3.69.254 internet IP 3.4.5.6
1254 D: net 10.4.0.0 mask 255.255.0.0 gateway 10.4.3.32 internet IP 4.5.6.7
1257 Here, ``gateway'' is the VPN IP address of the machine that is running the
1258 tincd, and ``internet IP'' is the IP address of the firewall, which does not
1259 need to run tincd, but it must do a port forwarding of TCP and UDP on port
1260 655 (unless otherwise configured).
1262 In this example, it is assumed that eth0 is the interface that points to
1263 the inner (physical) LAN of the office, although this could also be the
1264 same as the interface that leads to the Internet. The configuration of
1265 the real interface is also shown as a comment, to give you an idea of
1266 how these example host is set up. All branches use the netname `company'
1267 for this particular VPN.
1269 @subsubheading For Branch A
1271 @emph{BranchA} would be configured like this:
1273 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1276 # Real interface of internal network:
1277 # ifconfig eth0 10.1.54.1 netmask 255.255.0.0
1279 ifconfig $INTERFACE 10.1.54.1 netmask 255.0.0.0
1282 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1289 On all hosts, @file{@value{sysconfdir}/tinc/company/hosts/BranchA} contains:
1292 Subnet = 10.1.0.0/16
1295 -----BEGIN RSA PUBLIC KEY-----
1297 -----END RSA PUBLIC KEY-----
1300 Note that the IP addresses of eth0 and tap0 are the same.
1301 This is quite possible, if you make sure that the netmasks of the interfaces are different.
1302 It is in fact recommended to give give both real internal network interfaces and tap interfaces the same IP address,
1303 since that will make things a lot easier to remember and set up.
1306 @subsubheading For Branch B
1308 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1311 # Real interface of internal network:
1312 # ifconfig eth0 10.2.43.8 netmask 255.255.0.0
1314 ifconfig $INTERFACE 10.2.1.12 netmask 255.0.0.0
1317 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1324 Note here that the internal address (on eth0) doesn't have to be the
1325 same as on the tap0 device. Also, ConnectTo is given so that no-one can
1326 connect to this node.
1328 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchB}:
1331 Subnet = 10.2.0.0/16
1334 -----BEGIN RSA PUBLIC KEY-----
1336 -----END RSA PUBLIC KEY-----
1340 @subsubheading For Branch C
1342 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1345 # Real interface of internal network:
1346 # ifconfig eth0 10.3.69.254 netmask 255.255.0.0
1348 ifconfig $INTERFACE 10.3.69.254 netmask 255.0.0.0
1351 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1359 C already has another daemon that runs on port 655, so they have to
1360 reserve another port for tinc. It knows the portnumber it has to listen on
1361 from it's own host configuration file.
1363 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchC}:
1367 Subnet = 10.3.0.0/16
1370 -----BEGIN RSA PUBLIC KEY-----
1372 -----END RSA PUBLIC KEY-----
1376 @subsubheading For Branch D
1378 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1381 # Real interface of internal network:
1382 # ifconfig eth0 10.4.3.32 netmask 255.255.0.0
1384 ifconfig $INTERFACE 10.4.3.32 netmask 255.0.0.0
1387 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1392 Device = /dev/net/tun
1395 D will be connecting to C, which has a tincd running for this network on
1396 port 2000. It knows the port number from the host configuration file.
1397 Also note that since D uses the tun/tap driver, the network interface
1398 will not be called `tun' or `tap0' or something like that, but will
1399 have the same name as netname.
1401 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchD}:
1404 Subnet = 10.4.0.0/16
1407 -----BEGIN RSA PUBLIC KEY-----
1409 -----END RSA PUBLIC KEY-----
1412 @subsubheading Key files
1414 A, B, C and D all have generated a public/private keypair with the following command:
1420 The private key is stored in @file{@value{sysconfdir}/tinc/company/rsa_key.priv},
1421 the public key is put into the host configuration file in the @file{@value{sysconfdir}/tinc/company/hosts/} directory.
1422 During key generation, tinc automatically guesses the right filenames based on the -n option and
1423 the Name directive in the @file{tinc.conf} file (if it is available).
1425 @subsubheading Starting
1427 After each branch has finished configuration and they have distributed
1428 the host configuration files amongst them, they can start their tinc daemons.
1429 They don't necessarily have to wait for the other branches to have started
1430 their daemons, tinc will try connecting until they are available.
1433 @c ==================================================================
1435 @chapter Running tinc
1437 If everything else is done, you can start tinc by typing the following command:
1440 tincd -n @var{netname}
1444 Tinc will detach from the terminal and continue to run in the background like a good daemon.
1445 If there are any problems however you can try to increase the debug level
1446 and look in the syslog to find out what the problems are.
1452 * Solving problems::
1454 * Sending bug reports::
1458 @c ==================================================================
1459 @node Runtime options
1460 @section Runtime options
1462 Besides the settings in the configuration file, tinc also accepts some
1463 command line options.
1465 @cindex command line
1466 @cindex runtime options
1470 @item -c, --config=@var{path}
1471 Read configuration options from the directory @var{path}. The default is
1472 @file{@value{sysconfdir}/tinc/@var{netname}/}.
1474 @item -D, --no-detach
1475 Don't fork and detach.
1476 This will also disable the automatic restart mechanism for fatal errors.
1479 @item -d, --debug=@var{level}
1480 Set debug level to @var{level}. The higher the debug level, the more gets
1481 logged. Everything goes via syslog.
1483 @item -k, --kill[=@var{signal}]
1484 Attempt to kill a running tincd (optionally with the specified @var{signal} instead of SIGTERM) and exit.
1485 Use it in conjunction with the -n option to make sure you kill the right tinc daemon.
1486 Under native Windows the optional argument is ignored,
1487 the service will always be stopped and removed.
1489 @item -n, --net=@var{netname}
1490 Use configuration for net @var{netname}. @xref{Multiple networks}.
1492 @item -K, --generate-keys[=@var{bits}]
1493 Generate public/private keypair of @var{bits} length. If @var{bits} is not specified,
1494 1024 is the default. tinc will ask where you want to store the files,
1495 but will default to the configuration directory (you can use the -c or -n option
1496 in combination with -K). After that, tinc will quit.
1499 Lock tinc into main memory.
1500 This will prevent sensitive data like shared private keys to be written to the system swap files/partitions.
1502 @item --logfile[=@var{file}]
1503 Write log entries to a file instead of to the system logging facility.
1504 If @var{file} is omitted, the default is @file{@value{localstatedir}/log/tinc.@var{netname}.log}.
1506 @item --pidfile=@var{file}
1507 Write PID to @var{file} instead of @file{@value{localstatedir}/run/tinc.@var{netname}.pid}.
1509 @item --bypass-security
1510 Disables encryption and authentication.
1511 Only useful for debugging.
1514 Change process root directory to the directory where the config file is
1515 located (@file{@value{sysconfdir}/tinc/@var{netname}/} as determined by
1516 -n/--net option or as given by -c/--config option), for added security.
1517 The chroot is performed after all the initialization is done, after
1518 writing pid files and opening network sockets.
1520 Note that this option alone does not do any good without -U/--user, below.
1522 Note also that tinc can't run scripts anymore (such as tinc-down or host-up),
1523 unless it's setup to be runnable inside chroot environment.
1525 @item -U, --user=@var{user}
1526 Switch to the given @var{user} after initialization, at the same time as
1527 chroot is performed (see --chroot above). With this option tinc drops
1528 privileges, for added security.
1531 Display a short reminder of these runtime options and terminate.
1534 Output version information and exit.
1538 @c ==================================================================
1543 You can also send the following signals to a running tincd process:
1549 Forces tinc to try to connect to all uplinks immediately.
1550 Usually tinc attempts to do this itself,
1551 but increases the time it waits between the attempts each time it failed,
1552 and if tinc didn't succeed to connect to an uplink the first time after it started,
1553 it defaults to the maximum time of 15 minutes.
1556 Partially rereads configuration files.
1557 Connections to hosts whose host config file are removed are closed.
1558 New outgoing connections specified in @file{tinc.conf} will be made.
1561 Temporarily increases debug level to 5.
1562 Send this signal again to revert to the original level.
1565 Dumps the connection list to syslog.
1568 Dumps virtual network device statistics, all known nodes, edges and subnets to syslog.
1571 Purges all information remembered about unreachable nodes.
1575 @c ==================================================================
1577 @section Debug levels
1579 @cindex debug levels
1580 The tinc daemon can send a lot of messages to the syslog.
1581 The higher the debug level, the more messages it will log.
1582 Each level inherits all messages of the previous level:
1588 This will log a message indicating tinc has started along with a version number.
1589 It will also log any serious error.
1592 This will log all connections that are made with other tinc daemons.
1595 This will log status and error messages from scripts and other tinc daemons.
1598 This will log all requests that are exchanged with other tinc daemons. These include
1599 authentication, key exchange and connection list updates.
1602 This will log a copy of everything received on the meta socket.
1605 This will log all network traffic over the virtual private network.
1609 @c ==================================================================
1610 @node Solving problems
1611 @section Solving problems
1613 If tinc starts without problems, but if the VPN doesn't work, you will have to find the cause of the problem.
1614 The first thing to do is to start tinc with a high debug level in the foreground,
1615 so you can directly see everything tinc logs:
1618 tincd -n @var{netname} -d5 -D
1621 If tinc does not log any error messages, then you might want to check the following things:
1624 @item @file{tinc-up} script
1625 Does this script contain the right commands?
1626 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.
1629 Does the Subnet (or Subnets) in the host configuration file of this host match the portion of the VPN that belongs to this host?
1631 @item Firewalls and NATs
1632 Do you have a firewall or a NAT device (a masquerading firewall or perhaps an ADSL router that performs masquerading)?
1633 If so, check that it allows TCP and UDP traffic on port 655.
1634 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.
1635 You can add @samp{TCPOnly = yes} to your host config file to force tinc to only use a single TCP connection,
1636 this works through most firewalls and NATs.
1641 @c ==================================================================
1642 @node Error messages
1643 @section Error messages
1645 What follows is a list of the most common error messages you might find in the logs.
1646 Some of them will only be visible if the debug level is high enough.
1649 @item Could not open /dev/tap0: No such device
1652 @item You forgot to `modprobe netlink_dev' or `modprobe ethertap'.
1653 @item You forgot to compile `Netlink device emulation' in the kernel.
1656 @item Can't write to /dev/net/tun: No such device
1659 @item You forgot to `modprobe tun'.
1660 @item You forgot to compile `Universal TUN/TAP driver' in the kernel.
1661 @item The tun device is located somewhere else in @file{/dev/}.
1664 @item Network address and prefix length do not match!
1667 @item The Subnet field must contain a @emph{network} address, trailing bits should be 0.
1668 @item If you only want to use one IP address, set the netmask to /32.
1671 @item Error reading RSA key file `rsa_key.priv': No such file or directory
1674 @item You forgot to create a public/private keypair.
1675 @item Specify the complete pathname to the private key file with the @samp{PrivateKeyFile} option.
1678 @item Warning: insecure file permissions for RSA private key file `rsa_key.priv'!
1681 @item The private key file is readable by users other than root.
1682 Use chmod to correct the file permissions.
1685 @item Creating metasocket failed: Address family not supported
1688 @item By default tinc tries to create both IPv4 and IPv6 sockets.
1689 On some platforms this might not be implemented.
1690 If the logs show @samp{Ready} later on, then at least one metasocket was created,
1691 and you can ignore this message.
1692 You can add @samp{AddressFamily = ipv4} to @file{tinc.conf} to prevent this from happening.
1695 @item Cannot route packet: unknown IPv4 destination 1.2.3.4
1698 @item You try to send traffic to a host on the VPN for which no Subnet is known.
1699 @item If it is a broadcast address (ending in .255), it probably is a samba server or a Windows host sending broadcast packets.
1703 @item Cannot route packet: ARP request for unknown address 1.2.3.4
1706 @item You try to send traffic to a host on the VPN for which no Subnet is known.
1709 @item Packet with destination 1.2.3.4 is looping back to us!
1712 @item Something is not configured right. Packets are being sent out to the
1713 virtual network device, but according to the Subnet directives in your host configuration
1714 file, those packets should go to your own host. Most common mistake is that
1715 you have a Subnet line in your host configuration file with a prefix length which is
1716 just as large as the prefix of the virtual network interface. The latter should in almost all
1717 cases be larger. Rethink your configuration.
1718 Note that you will only see this message if you specified a debug
1719 level of 5 or higher!
1720 @item Chances are that a @samp{Subnet = ...} line in the host configuration file of this tinc daemon is wrong.
1721 Change it to a subnet that is accepted locally by another interface,
1722 or if that is not the case, try changing the prefix length into /32.
1725 @item Node foo (1.2.3.4) is not reachable
1728 @item Node foo does not have a connection anymore, its tinc daemon is not running or its connection to the Internet is broken.
1731 @item Received UDP packet from unknown source 1.2.3.4 (port 12345)
1734 @item If you see this only sporadically, it is harmless and caused by a node sending packets using an old key.
1735 @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.
1736 You can add @samp{TCPOnly = yes} to host configuration files to force all VPN traffic to go over a TCP connection.
1739 @item Got bad/bogus/unauthorized REQUEST from foo (1.2.3.4 port 12345)
1742 @item Node foo does not have the right public/private keypair.
1743 Generate new keypairs and distribute them again.
1744 @item An attacker tries to gain access to your VPN.
1745 @item A network error caused corruption of metadata sent from foo.
1750 @c ==================================================================
1751 @node Sending bug reports
1752 @section Sending bug reports
1754 If you really can't find the cause of a problem, or if you suspect tinc is not working right,
1755 you can send us a bugreport, see @ref{Contact information}.
1756 Be sure to include the following information in your bugreport:
1759 @item A clear description of what you are trying to achieve and what the problem is.
1760 @item What platform (operating system, version, hardware architecture) and which version of tinc you use.
1761 @item If compiling tinc fails, a copy of @file{config.log} and the error messages you get.
1762 @item Otherwise, a copy of @file{tinc.conf}, @file{tinc-up} and all files in the @file{hosts/} directory.
1763 @item The output of the commands @samp{ifconfig -a} and @samp{route -n} (or @samp{netstat -rn} if that doesn't work).
1764 @item The output of any command that fails to work as it should (like ping or traceroute).
1767 @c ==================================================================
1768 @node Technical information
1769 @chapter Technical information
1774 * The meta-protocol::
1779 @c ==================================================================
1780 @node The connection
1781 @section The connection
1784 Tinc is a daemon that takes VPN data and transmit that to another host
1785 computer over the existing Internet infrastructure.
1789 * The meta-connection::
1793 @c ==================================================================
1794 @node The UDP tunnel
1795 @subsection The UDP tunnel
1797 @cindex virtual network device
1799 The data itself is read from a character device file, the so-called
1800 @emph{virtual network device}. This device is associated with a network
1801 interface. Any data sent to this interface can be read from the device,
1802 and any data written to the device gets sent from the interface.
1803 There are two possible types of virtual network devices:
1804 `tun' style, which are point-to-point devices which can only handle IPv4 and/or IPv6 packets,
1805 and `tap' style, which are Ethernet devices and handle complete Ethernet frames.
1807 So when tinc reads an Ethernet frame from the device, it determines its
1808 type. When tinc is in it's default routing mode, it can handle IPv4 and IPv6
1809 packets. Depending on the Subnet lines, it will send the packets off to their destination IP address.
1810 In the `switch' and `hub' mode, tinc will use broadcasts and MAC address discovery
1811 to deduce the destination of the packets.
1812 Since the latter modes only depend on the link layer information,
1813 any protocol that runs over Ethernet is supported (for instance IPX and Appletalk).
1814 However, only `tap' style devices provide this information.
1816 After the destination has been determined,
1817 the packet will be compressed (optionally),
1818 a sequence number will be added to the packet,
1819 the packet will then be encrypted
1820 and a message authentication code will be appended.
1822 @cindex encapsulating
1824 When that is done, time has come to actually transport the
1825 packet to the destination computer. We do this by sending the packet
1826 over an UDP connection to the destination host. This is called
1827 @emph{encapsulating}, the VPN packet (though now encrypted) is
1828 encapsulated in another IP datagram.
1830 When the destination receives this packet, the same thing happens, only
1831 in reverse. So it checks the message authentication code, decrypts the contents of the UDP datagram,
1832 checks the sequence number
1833 and writes the decrypted information to its own virtual network device.
1835 If the virtual network device is a `tun' device (a point-to-point tunnel),
1836 there is no problem for the kernel to accept a packet.
1837 However, if it is a `tap' device (this is the only available type on FreeBSD),
1838 the destination MAC address must match that of the virtual network interface.
1839 If tinc is in it's default routing mode, ARP does not work, so the correct destination MAC
1840 can not be known by the sending host.
1841 Tinc solves this by letting the receiving end detect the MAC address of its own virtual network interface
1842 and overwriting the destination MAC address of the received packet.
1844 In switch or hub modes ARP does work so the sender already knows the correct destination MAC address.
1845 In those modes every interface should have a unique MAC address, so make sure they are not the same.
1846 Because switch and hub modes rely on MAC addresses to function correctly,
1847 these modes cannot be used on the following operating systems which don't have a `tap' style virtual network device:
1848 OpenBSD, NetBSD, Darwin and Solaris.
1851 @c ==================================================================
1852 @node The meta-connection
1853 @subsection The meta-connection
1855 Having only a UDP connection available is not enough. Though suitable
1856 for transmitting data, we want to be able to reliably send other
1857 information, such as routing and session key information to somebody.
1860 TCP is a better alternative, because it already contains protection
1861 against information being lost, unlike UDP.
1863 So we establish two connections. One for the encrypted VPN data, and one
1864 for other information, the meta-data. Hence, we call the second
1865 connection the meta-connection. We can now be sure that the
1866 meta-information doesn't get lost on the way to another computer.
1868 @cindex data-protocol
1869 @cindex meta-protocol
1870 Like with any communication, we must have a protocol, so that everybody
1871 knows what everything stands for, and how she should react. Because we
1872 have two connections, we also have two protocols. The protocol used for
1873 the UDP data is the ``data-protocol,'' the other one is the
1876 The reason we don't use TCP for both protocols is that UDP is much
1877 better for encapsulation, even while it is less reliable. The real
1878 problem is that when TCP would be used to encapsulate a TCP stream
1879 that's on the private network, for every packet sent there would be
1880 three ACKs sent instead of just one. Furthermore, if there would be
1881 a timeout, both TCP streams would sense the timeout, and both would
1882 start re-sending packets.
1885 @c ==================================================================
1886 @node The meta-protocol
1887 @section The meta-protocol
1889 The meta protocol is used to tie all tinc daemons together, and
1890 exchange information about which tinc daemon serves which virtual
1893 The meta protocol consists of requests that can be sent to the other
1894 side. Each request has a unique number and several parameters. All
1895 requests are represented in the standard ASCII character set. It is
1896 possible to use tools such as telnet or netcat to connect to a tinc
1897 daemon started with the --bypass-security option
1898 and to read and write requests by hand, provided that one
1899 understands the numeric codes sent.
1901 The authentication scheme is described in @ref{Authentication protocol}. After a
1902 successful authentication, the server and the client will exchange all the
1903 information about other tinc daemons and subnets they know of, so that both
1904 sides (and all the other tinc daemons behind them) have their information
1911 ------------------------------------------------------------------
1912 ADD_EDGE node1 node2 21.32.43.54 655 222 0
1913 | | | | | +-> options
1914 | | | | +----> weight
1915 | | | +--------> UDP port of node2
1916 | | +----------------> real address of node2
1917 | +-------------------------> name of destination node
1918 +-------------------------------> name of source node
1920 ADD_SUBNET node 192.168.1.0/24
1921 | | +--> prefixlength
1922 | +--------> network address
1923 +------------------> owner of this subnet
1924 ------------------------------------------------------------------
1927 The ADD_EDGE messages are to inform other tinc daemons that a connection between
1928 two nodes exist. The address of the destination node is available so that
1929 VPN packets can be sent directly to that node.
1931 The ADD_SUBNET messages inform other tinc daemons that certain subnets belong
1932 to certain nodes. tinc will use it to determine to which node a VPN packet has
1939 ------------------------------------------------------------------
1940 DEL_EDGE node1 node2
1941 | +----> name of destination node
1942 +----------> name of source node
1944 DEL_SUBNET node 192.168.1.0/24
1945 | | +--> prefixlength
1946 | +--------> network address
1947 +------------------> owner of this subnet
1948 ------------------------------------------------------------------
1951 In case a connection between two daemons is closed or broken, DEL_EDGE messages
1952 are sent to inform the other daemons of that fact. Each daemon will calculate a
1953 new route to the the daemons, or mark them unreachable if there isn't any.
1960 ------------------------------------------------------------------
1961 REQ_KEY origin destination
1962 | +--> name of the tinc daemon it wants the key from
1963 +----------> name of the daemon that wants the key
1965 ANS_KEY origin destination 4ae0b0a82d6e0078 91 64 4
1966 | | \______________/ | | +--> MAC length
1967 | | | | +-----> digest algorithm
1968 | | | +--------> cipher algorithm
1969 | | +--> 128 bits key
1970 | +--> name of the daemon that wants the key
1971 +----------> name of the daemon that uses this key
1974 +--> daemon that has changed it's packet key
1975 ------------------------------------------------------------------
1978 The keys used to encrypt VPN packets are not sent out directly. This is
1979 because it would generate a lot of traffic on VPNs with many daemons, and
1980 chances are that not every tinc daemon will ever send a packet to every
1981 other daemon. Instead, if a daemon needs a key it sends a request for it
1982 via the meta connection of the nearest hop in the direction of the
1989 ------------------------------------------------------------------
1992 ------------------------------------------------------------------
1995 There is also a mechanism to check if hosts are still alive. Since network
1996 failures or a crash can cause a daemon to be killed without properly
1997 shutting down the TCP connection, this is necessary to keep an up to date
1998 connection list. PINGs are sent at regular intervals, except when there
1999 is also some other traffic. A little bit of salt (random data) is added
2000 with each PING and PONG message, to make sure that long sequences of PING/PONG
2001 messages without any other traffic won't result in known plaintext.
2003 This basically covers what is sent over the meta connection by tinc.
2006 @c ==================================================================
2012 Tinc got its name from ``TINC,'' short for @emph{There Is No Cabal}; the
2013 alleged Cabal was/is an organisation that was said to keep an eye on the
2014 entire Internet. As this is exactly what you @emph{don't} want, we named
2015 the tinc project after TINC.
2018 But in order to be ``immune'' to eavesdropping, you'll have to encrypt
2019 your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does
2020 exactly that: encrypt.
2021 Tinc by default uses blowfish encryption with 128 bit keys in CBC mode, 32 bit
2022 sequence numbers and 4 byte long message authentication codes to make sure
2023 eavesdroppers cannot get and cannot change any information at all from the
2024 packets they can intercept. The encryption algorithm and message authentication
2025 algorithm can be changed in the configuration. The length of the message
2026 authentication codes is also adjustable. The length of the key for the
2027 encryption algorithm is always the default length used by OpenSSL.
2030 * Authentication protocol::
2031 * Encryption of network packets::
2036 @c ==================================================================
2037 @node Authentication protocol
2038 @subsection Authentication protocol
2040 @cindex authentication
2041 A new scheme for authentication in tinc has been devised, which offers some
2042 improvements over the protocol used in 1.0pre2 and 1.0pre3. Explanation is
2052 --------------------------------------------------------------------------
2053 client <attempts connection>
2055 server <accepts connection>
2059 +-------> name of tinc daemon
2063 +-------> name of tinc daemon
2065 client META_KEY 5f0823a93e35b69e...7086ec7866ce582b
2066 \_________________________________/
2067 +-> RSAKEYLEN bits totally random string S1,
2068 encrypted with server's public RSA key
2070 server META_KEY 6ab9c1640388f8f0...45d1a07f8a672630
2071 \_________________________________/
2072 +-> RSAKEYLEN bits totally random string S2,
2073 encrypted with client's public RSA key
2076 - the client will symmetrically encrypt outgoing traffic using S1
2077 - the server will symmetrically encrypt outgoing traffic using S2
2079 client CHALLENGE da02add1817c1920989ba6ae2a49cecbda0
2080 \_________________________________/
2081 +-> CHALLEN bits totally random string H1
2083 server CHALLENGE 57fb4b2ccd70d6bb35a64c142f47e61d57f
2084 \_________________________________/
2085 +-> CHALLEN bits totally random string H2
2087 client CHAL_REPLY 816a86
2088 +-> 160 bits SHA1 of H2
2090 server CHAL_REPLY 928ffe
2091 +-> 160 bits SHA1 of H1
2093 After the correct challenge replies are received, both ends have proved
2094 their identity. Further information is exchanged.
2096 client ACK 655 123 0
2098 | +----> estimated weight
2099 +--------> listening port of client
2101 server ACK 655 321 0
2103 | +----> estimated weight
2104 +--------> listening port of server
2105 --------------------------------------------------------------------------
2108 This new scheme has several improvements, both in efficiency and security.
2110 First of all, the server sends exactly the same kind of messages over the wire
2111 as the client. The previous versions of tinc first authenticated the client,
2112 and then the server. This scheme even allows both sides to send their messages
2113 simultaneously, there is no need to wait for the other to send something first.
2114 This means that any calculations that need to be done upon sending or receiving
2115 a message can also be done in parallel. This is especially important when doing
2116 RSA encryption/decryption. Given that these calculations are the main part of
2117 the CPU time spent for the authentication, speed is improved by a factor 2.
2119 Second, only one RSA encrypted message is sent instead of two. This reduces the
2120 amount of information attackers can see (and thus use for a cryptographic
2121 attack). It also improves speed by a factor two, making the total speedup a
2124 Third, and most important:
2125 The symmetric cipher keys are exchanged first, the challenge is done
2126 afterwards. In the previous authentication scheme, because a man-in-the-middle
2127 could pass the challenge/chal_reply phase (by just copying the messages between
2128 the two real tinc daemons), but no information was exchanged that was really
2129 needed to read the rest of the messages, the challenge/chal_reply phase was of
2130 no real use. The man-in-the-middle was only stopped by the fact that only after
2131 the ACK messages were encrypted with the symmetric cipher. Potentially, it
2132 could even send it's own symmetric key to the server (if it knew the server's
2133 public key) and read some of the metadata the server would send it (it was
2134 impossible for the mitm to read actual network packets though). The new scheme
2135 however prevents this.
2137 This new scheme makes sure that first of all, symmetric keys are exchanged. The
2138 rest of the messages are then encrypted with the symmetric cipher. Then, each
2139 side can only read received messages if they have their private key. The
2140 challenge is there to let the other side know that the private key is really
2141 known, because a challenge reply can only be sent back if the challenge is
2142 decrypted correctly, and that can only be done with knowledge of the private
2145 Fourth: the first thing that is sent via the symmetric cipher encrypted
2146 connection is a totally random string, so that there is no known plaintext (for
2147 an attacker) in the beginning of the encrypted stream.
2150 @c ==================================================================
2151 @node Encryption of network packets
2152 @subsection Encryption of network packets
2155 A data packet can only be sent if the encryption key is known to both
2156 parties, and the connection is activated. If the encryption key is not
2157 known, a request is sent to the destination using the meta connection
2158 to retrieve it. The packet is stored in a queue while waiting for the
2162 The UDP packet containing the network packet from the VPN has the following layout:
2165 ... | IP header | UDP header | seqno | VPN packet | MAC | UDP trailer
2166 \___________________/\_____/
2168 V +---> digest algorithm
2169 Encrypted with symmetric cipher
2172 So, the entire VPN packet is encrypted using a symmetric cipher, including a 32 bits
2173 sequence number that is added in front of the actual VPN packet, to act as a unique
2174 IV for each packet and to prevent replay attacks. A message authentication code
2175 is added to the UDP packet to prevent alteration of packets. By default the
2176 first 4 bytes of the digest are used for this, but this can be changed using
2177 the MACLength configuration variable.
2179 @c ==================================================================
2180 @node Security issues
2181 @subsection Security issues
2183 In August 2000, we discovered the existence of a security hole in all versions
2184 of tinc up to and including 1.0pre2. This had to do with the way we exchanged
2185 keys. Since then, we have been working on a new authentication scheme to make
2186 tinc as secure as possible. The current version uses the OpenSSL library and
2187 uses strong authentication with RSA keys.
2189 On the 29th of December 2001, Jerome Etienne posted a security analysis of tinc
2190 1.0pre4. Due to a lack of sequence numbers and a message authentication code
2191 for each packet, an attacker could possibly disrupt certain network services or
2192 launch a denial of service attack by replaying intercepted packets. The current
2193 version adds sequence numbers and message authentication codes to prevent such
2196 On the 15th of September 2003, Peter Gutmann posted a security analysis of tinc
2197 1.0.1. He argues that the 32 bit sequence number used by tinc is not a good IV,
2198 that tinc's default length of 4 bytes for the MAC is too short, and he doesn't
2199 like tinc's use of RSA during authentication. We do not know of a security hole
2200 in this version of tinc, but tinc's security is not as strong as TLS or IPsec.
2201 We will address these issues in tinc 2.0.
2203 Cryptography is a hard thing to get right. We cannot make any
2204 guarantees. Time, review and feedback are the only things that can
2205 prove the security of any cryptographic product. If you wish to review
2206 tinc or give us feedback, you are stronly encouraged to do so.
2209 @c ==================================================================
2210 @node Platform specific information
2211 @chapter Platform specific information
2214 * Interface configuration::
2218 @c ==================================================================
2219 @node Interface configuration
2220 @section Interface configuration
2222 When configuring an interface, one normally assigns it an address and a
2223 netmask. The address uniquely identifies the host on the network attached to
2224 the interface. The netmask, combined with the address, forms a subnet. It is
2225 used to add a route to the routing table instructing the kernel to send all
2226 packets which fall into that subnet to that interface. Because all packets for
2227 the entire VPN should go to the virtual network interface used by tinc, the
2228 netmask should be such that it encompasses the entire VPN.
2232 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2234 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2235 @item Linux iproute2
2236 @tab @code{ip addr add} @var{address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2238 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2240 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2242 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2244 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2245 @item Darwin (MacOS/X)
2246 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2248 @tab @code{netsh interface ip set address} @var{interface} @code{static} @var{address} @var{netmask}
2254 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2256 @tab @code{ifconfig} @var{interface} @code{add} @var{address}@code{/}@var{prefixlength}
2258 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2260 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2262 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2264 @tab @code{ifconfig} @var{interface} @code{inet6 plumb up}
2266 @tab @code{ifconfig} @var{interface} @code{inet6 addif} @var{address} @var{address}
2267 @item Darwin (MacOS/X)
2268 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2270 @tab @code{netsh interface ipv6 add address} @var{interface} @code{static} @var{address}/@var{prefixlength}
2274 @c ==================================================================
2278 In some cases it might be necessary to add more routes to the virtual network
2279 interface. There are two ways to indicate which interface a packet should go
2280 to, one is to use the name of the interface itself, another way is to specify
2281 the (local) address that is assigned to that interface (@var{local_address}). The
2282 former way is unambiguous and therefore preferable, but not all platforms
2285 Adding routes to IPv4 subnets:
2287 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2289 @tab @code{route add -net} @var{network_address} @code{netmask} @var{netmask} @var{interface}
2290 @item Linux iproute2
2291 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2293 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2295 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2297 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2299 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
2300 @item Darwin (MacOS/X)
2301 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2303 @tab @code{netsh routing ip add persistentroute} @var{network_address} @var{netmask} @var{interface} @var{local_address}
2306 Adding routes to IPv6 subnets:
2308 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2310 @tab @code{route add -A inet6} @var{network_address}@code{/}@var{prefixlength} @var{interface}
2311 @item Linux iproute2
2312 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2314 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2316 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
2318 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
2320 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
2321 @item Darwin (MacOS/X)
2324 @tab @code{netsh interface ipv6 add route} @var{network address}/@var{prefixlength} @var{interface}
2328 @c ==================================================================
2334 * Contact information::
2339 @c ==================================================================
2340 @node Contact information
2341 @section Contact information
2344 Tinc's website is at @url{http://www.tinc-vpn.org/},
2345 this server is located in the Netherlands.
2348 We have an IRC channel on the FreeNode and OFTC IRC networks. Connect to
2349 @uref{http://www.freenode.net/, irc.freenode.net}
2351 @uref{http://www.oftc.net/, irc.oftc.net}
2352 and join channel #tinc.
2355 @c ==================================================================
2360 @item Ivo Timmermans (zarq)
2361 @item Guus Sliepen (guus) (@email{guus@@tinc-vpn.org})
2364 We have received a lot of valuable input from users. With their help,
2365 tinc has become the flexible and robust tool that it is today. We have
2366 composed a list of contributions, in the file called @file{THANKS} in
2367 the source distribution.
2370 @c ==================================================================
2372 @unnumbered Concept Index
2374 @c ==================================================================
2378 @c ==================================================================