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 @cindex Subnet weight
1042 A Subnet can be given a weight to indicate its priority over identical Subnets
1043 owned by different nodes. The default weight is 10. Lower values indicate
1044 higher priority. Packets will be sent to the node with the highest priority,
1045 unless that node is not reachable, in which case the node with the next highest
1046 priority will be tried, and so on.
1049 @item TCPonly = <yes|no> (no) [deprecated]
1050 If this variable is set to yes, then the packets are tunnelled over a
1051 TCP connection instead of a UDP connection. This is especially useful
1052 for those who want to run a tinc daemon from behind a masquerading
1053 firewall, or if UDP packet routing is disabled somehow.
1054 Setting this options also implicitly sets IndirectData.
1056 Since version 1.0.10, tinc will automatically detect whether communication via
1057 UDP is possible or not.
1061 @c ==================================================================
1066 Apart from reading the server and host configuration files,
1067 tinc can also run scripts at certain moments.
1068 Under Windows (not Cygwin), the scripts should have the extension .bat.
1072 @item @value{sysconfdir}/tinc/@var{netname}/tinc-up
1073 This is the most important script.
1074 If it is present it will be executed right after the tinc daemon has been
1075 started and has connected to the virtual network device.
1076 It should be used to set up the corresponding network interface,
1077 but can also be used to start other things.
1078 Under Windows you can use the Network Connections control panel instead of creating this script.
1081 @item @value{sysconfdir}/tinc/@var{netname}/tinc-down
1082 This script is started right before the tinc daemon quits.
1084 @item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-up
1085 This script is started when the tinc daemon with name @var{host} becomes reachable.
1087 @item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-down
1088 This script is started when the tinc daemon with name @var{host} becomes unreachable.
1090 @item @value{sysconfdir}/tinc/@var{netname}/host-up
1091 This script is started when any host becomes reachable.
1093 @item @value{sysconfdir}/tinc/@var{netname}/host-down
1094 This script is started when any host becomes unreachable.
1096 @item @value{sysconfdir}/tinc/@var{netname}/subnet-up
1097 This script is started when a Subnet becomes reachable.
1098 The Subnet and the node it belongs to are passed in environment variables.
1100 @item @value{sysconfdir}/tinc/@var{netname}/subnet-down
1101 This script is started when a Subnet becomes unreachable.
1104 @cindex environment variables
1105 The scripts are started without command line arguments,
1106 but can make use of certain environment variables.
1107 Under UNIX like operating systems the names of environment variables must be preceded by a $ in scripts.
1108 Under Windows, in @file{.bat} files, they have to be put between % signs.
1113 If a netname was specified, this environment variable contains it.
1117 Contains the name of this tinc daemon.
1121 Contains the name of the virtual network device that tinc uses.
1125 Contains the name of the virtual network interface that tinc uses.
1126 This should be used for commands like ifconfig.
1130 When a host becomes (un)reachable, this is set to its name.
1131 If a subnet becomes (un)reachable, this is set to the owner of that subnet.
1133 @cindex REMOTEADDRESS
1135 When a host becomes (un)reachable, this is set to its real address.
1139 When a host becomes (un)reachable,
1140 this is set to the port number it uses for communication with other tinc daemons.
1144 When a subnet becomes (un)reachable, this is set to the subnet.
1148 When a subnet becomes (un)reachable, this is set to the subnet weight.
1153 @c ==================================================================
1154 @node How to configure
1155 @subsection How to configure
1157 @subsubheading Step 1. Creating the main configuration file
1159 The main configuration file will be called @file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf}.
1160 Adapt the following example to create a basic configuration file:
1163 Name = @var{yourname}
1164 Device = @file{/dev/tap0}
1167 Then, if you know to which other tinc daemon(s) yours is going to connect,
1168 add `ConnectTo' values.
1170 @subsubheading Step 2. Creating your host configuration file
1172 If you added a line containing `Name = yourname' in the main configuarion file,
1173 you will need to create a host configuration file @file{@value{sysconfdir}/tinc/@var{netname}/hosts/yourname}.
1174 Adapt the following example to create a host configuration file:
1177 Address = your.real.hostname.org
1178 Subnet = 192.168.1.0/24
1181 You can also use an IP address instead of a hostname.
1182 The `Subnet' specifies the address range that is local for @emph{your part of the VPN only}.
1183 If you have multiple address ranges you can specify more than one `Subnet'.
1184 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).
1187 @c ==================================================================
1188 @node Generating keypairs
1189 @section Generating keypairs
1191 @cindex key generation
1192 Now that you have already created the main configuration file and your host configuration file,
1193 you can easily create a public/private keypair by entering the following command:
1196 tincd -n @var{netname} -K
1199 Tinc will generate a public and a private key and ask you where to put them.
1200 Just press enter to accept the defaults.
1203 @c ==================================================================
1204 @node Network interfaces
1205 @section Network interfaces
1207 Before tinc can start transmitting data over the tunnel, it must
1208 set up the virtual network interface.
1210 First, decide which IP addresses you want to have associated with these
1211 devices, and what network mask they must have.
1213 Tinc will open a virtual network device (@file{/dev/tun}, @file{/dev/tap0} or similar),
1214 which will also create a network interface called something like @samp{tun0}, @samp{tap0}.
1215 If you are using the Linux tun/tap driver, the network interface will by default have the same name as the @var{netname}.
1216 Under Windows you can change the name of the network interface from the Network Connections control panel.
1219 You can configure the network interface by putting ordinary ifconfig, route, and other commands
1220 to a script named @file{@value{sysconfdir}/tinc/@var{netname}/tinc-up}.
1221 When tinc starts, this script will be executed. When tinc exits, it will execute the script named
1222 @file{@value{sysconfdir}/tinc/@var{netname}/tinc-down}, but normally you don't need to create that script.
1224 An example @file{tinc-up} script:
1228 ifconfig $INTERFACE 192.168.1.1 netmask 255.255.0.0
1231 This script gives the interface an IP address and a netmask.
1232 The kernel will also automatically add a route to this interface, so normally you don't need
1233 to add route commands to the @file{tinc-up} script.
1234 The kernel will also bring the interface up after this command.
1236 The netmask is the mask of the @emph{entire} VPN network, not just your
1239 The exact syntax of the ifconfig and route commands differs from platform to platform.
1240 You can look up the commands for setting addresses and adding routes in @ref{Platform specific information},
1241 but it is best to consult the manpages of those utilities on your platform.
1244 @c ==================================================================
1245 @node Example configuration
1246 @section Example configuration
1250 Imagine the following situation. Branch A of our example `company' wants to connect
1251 three branch offices in B, C and D using the Internet. All four offices
1252 have a 24/7 connection to the Internet.
1254 A is going to serve as the center of the network. B and C will connect
1255 to A, and D will connect to C. Each office will be assigned their own IP
1259 A: net 10.1.0.0 mask 255.255.0.0 gateway 10.1.54.1 internet IP 1.2.3.4
1260 B: net 10.2.0.0 mask 255.255.0.0 gateway 10.2.1.12 internet IP 2.3.4.5
1261 C: net 10.3.0.0 mask 255.255.0.0 gateway 10.3.69.254 internet IP 3.4.5.6
1262 D: net 10.4.0.0 mask 255.255.0.0 gateway 10.4.3.32 internet IP 4.5.6.7
1265 Here, ``gateway'' is the VPN IP address of the machine that is running the
1266 tincd, and ``internet IP'' is the IP address of the firewall, which does not
1267 need to run tincd, but it must do a port forwarding of TCP and UDP on port
1268 655 (unless otherwise configured).
1270 In this example, it is assumed that eth0 is the interface that points to
1271 the inner (physical) LAN of the office, although this could also be the
1272 same as the interface that leads to the Internet. The configuration of
1273 the real interface is also shown as a comment, to give you an idea of
1274 how these example host is set up. All branches use the netname `company'
1275 for this particular VPN.
1277 @subsubheading For Branch A
1279 @emph{BranchA} would be configured like this:
1281 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1284 # Real interface of internal network:
1285 # ifconfig eth0 10.1.54.1 netmask 255.255.0.0
1287 ifconfig $INTERFACE 10.1.54.1 netmask 255.0.0.0
1290 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1297 On all hosts, @file{@value{sysconfdir}/tinc/company/hosts/BranchA} contains:
1300 Subnet = 10.1.0.0/16
1303 -----BEGIN RSA PUBLIC KEY-----
1305 -----END RSA PUBLIC KEY-----
1308 Note that the IP addresses of eth0 and tap0 are the same.
1309 This is quite possible, if you make sure that the netmasks of the interfaces are different.
1310 It is in fact recommended to give give both real internal network interfaces and tap interfaces the same IP address,
1311 since that will make things a lot easier to remember and set up.
1314 @subsubheading For Branch B
1316 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1319 # Real interface of internal network:
1320 # ifconfig eth0 10.2.43.8 netmask 255.255.0.0
1322 ifconfig $INTERFACE 10.2.1.12 netmask 255.0.0.0
1325 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1332 Note here that the internal address (on eth0) doesn't have to be the
1333 same as on the tap0 device. Also, ConnectTo is given so that no-one can
1334 connect to this node.
1336 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchB}:
1339 Subnet = 10.2.0.0/16
1342 -----BEGIN RSA PUBLIC KEY-----
1344 -----END RSA PUBLIC KEY-----
1348 @subsubheading For Branch C
1350 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1353 # Real interface of internal network:
1354 # ifconfig eth0 10.3.69.254 netmask 255.255.0.0
1356 ifconfig $INTERFACE 10.3.69.254 netmask 255.0.0.0
1359 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1367 C already has another daemon that runs on port 655, so they have to
1368 reserve another port for tinc. It knows the portnumber it has to listen on
1369 from it's own host configuration file.
1371 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchC}:
1375 Subnet = 10.3.0.0/16
1378 -----BEGIN RSA PUBLIC KEY-----
1380 -----END RSA PUBLIC KEY-----
1384 @subsubheading For Branch D
1386 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1389 # Real interface of internal network:
1390 # ifconfig eth0 10.4.3.32 netmask 255.255.0.0
1392 ifconfig $INTERFACE 10.4.3.32 netmask 255.0.0.0
1395 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1400 Device = /dev/net/tun
1403 D will be connecting to C, which has a tincd running for this network on
1404 port 2000. It knows the port number from the host configuration file.
1405 Also note that since D uses the tun/tap driver, the network interface
1406 will not be called `tun' or `tap0' or something like that, but will
1407 have the same name as netname.
1409 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchD}:
1412 Subnet = 10.4.0.0/16
1415 -----BEGIN RSA PUBLIC KEY-----
1417 -----END RSA PUBLIC KEY-----
1420 @subsubheading Key files
1422 A, B, C and D all have generated a public/private keypair with the following command:
1428 The private key is stored in @file{@value{sysconfdir}/tinc/company/rsa_key.priv},
1429 the public key is put into the host configuration file in the @file{@value{sysconfdir}/tinc/company/hosts/} directory.
1430 During key generation, tinc automatically guesses the right filenames based on the -n option and
1431 the Name directive in the @file{tinc.conf} file (if it is available).
1433 @subsubheading Starting
1435 After each branch has finished configuration and they have distributed
1436 the host configuration files amongst them, they can start their tinc daemons.
1437 They don't necessarily have to wait for the other branches to have started
1438 their daemons, tinc will try connecting until they are available.
1441 @c ==================================================================
1443 @chapter Running tinc
1445 If everything else is done, you can start tinc by typing the following command:
1448 tincd -n @var{netname}
1452 Tinc will detach from the terminal and continue to run in the background like a good daemon.
1453 If there are any problems however you can try to increase the debug level
1454 and look in the syslog to find out what the problems are.
1460 * Solving problems::
1462 * Sending bug reports::
1466 @c ==================================================================
1467 @node Runtime options
1468 @section Runtime options
1470 Besides the settings in the configuration file, tinc also accepts some
1471 command line options.
1473 @cindex command line
1474 @cindex runtime options
1478 @item -c, --config=@var{path}
1479 Read configuration options from the directory @var{path}. The default is
1480 @file{@value{sysconfdir}/tinc/@var{netname}/}.
1482 @item -D, --no-detach
1483 Don't fork and detach.
1484 This will also disable the automatic restart mechanism for fatal errors.
1487 @item -d, --debug=@var{level}
1488 Set debug level to @var{level}. The higher the debug level, the more gets
1489 logged. Everything goes via syslog.
1491 @item -k, --kill[=@var{signal}]
1492 Attempt to kill a running tincd (optionally with the specified @var{signal} instead of SIGTERM) and exit.
1493 Use it in conjunction with the -n option to make sure you kill the right tinc daemon.
1494 Under native Windows the optional argument is ignored,
1495 the service will always be stopped and removed.
1497 @item -n, --net=@var{netname}
1498 Use configuration for net @var{netname}. @xref{Multiple networks}.
1500 @item -K, --generate-keys[=@var{bits}]
1501 Generate public/private keypair of @var{bits} length. If @var{bits} is not specified,
1502 2048 is the default. tinc will ask where you want to store the files,
1503 but will default to the configuration directory (you can use the -c or -n option
1504 in combination with -K). After that, tinc will quit.
1507 Lock tinc into main memory.
1508 This will prevent sensitive data like shared private keys to be written to the system swap files/partitions.
1510 @item --logfile[=@var{file}]
1511 Write log entries to a file instead of to the system logging facility.
1512 If @var{file} is omitted, the default is @file{@value{localstatedir}/log/tinc.@var{netname}.log}.
1514 @item --pidfile=@var{file}
1515 Write PID to @var{file} instead of @file{@value{localstatedir}/run/tinc.@var{netname}.pid}.
1517 @item --bypass-security
1518 Disables encryption and authentication.
1519 Only useful for debugging.
1522 Change process root directory to the directory where the config file is
1523 located (@file{@value{sysconfdir}/tinc/@var{netname}/} as determined by
1524 -n/--net option or as given by -c/--config option), for added security.
1525 The chroot is performed after all the initialization is done, after
1526 writing pid files and opening network sockets.
1528 Note that this option alone does not do any good without -U/--user, below.
1530 Note also that tinc can't run scripts anymore (such as tinc-down or host-up),
1531 unless it's setup to be runnable inside chroot environment.
1533 @item -U, --user=@var{user}
1534 Switch to the given @var{user} after initialization, at the same time as
1535 chroot is performed (see --chroot above). With this option tinc drops
1536 privileges, for added security.
1539 Display a short reminder of these runtime options and terminate.
1542 Output version information and exit.
1546 @c ==================================================================
1551 You can also send the following signals to a running tincd process:
1557 Forces tinc to try to connect to all uplinks immediately.
1558 Usually tinc attempts to do this itself,
1559 but increases the time it waits between the attempts each time it failed,
1560 and if tinc didn't succeed to connect to an uplink the first time after it started,
1561 it defaults to the maximum time of 15 minutes.
1564 Partially rereads configuration files.
1565 Connections to hosts whose host config file are removed are closed.
1566 New outgoing connections specified in @file{tinc.conf} will be made.
1569 Temporarily increases debug level to 5.
1570 Send this signal again to revert to the original level.
1573 Dumps the connection list to syslog.
1576 Dumps virtual network device statistics, all known nodes, edges and subnets to syslog.
1579 Purges all information remembered about unreachable nodes.
1583 @c ==================================================================
1585 @section Debug levels
1587 @cindex debug levels
1588 The tinc daemon can send a lot of messages to the syslog.
1589 The higher the debug level, the more messages it will log.
1590 Each level inherits all messages of the previous level:
1596 This will log a message indicating tinc has started along with a version number.
1597 It will also log any serious error.
1600 This will log all connections that are made with other tinc daemons.
1603 This will log status and error messages from scripts and other tinc daemons.
1606 This will log all requests that are exchanged with other tinc daemons. These include
1607 authentication, key exchange and connection list updates.
1610 This will log a copy of everything received on the meta socket.
1613 This will log all network traffic over the virtual private network.
1617 @c ==================================================================
1618 @node Solving problems
1619 @section Solving problems
1621 If tinc starts without problems, but if the VPN doesn't work, you will have to find the cause of the problem.
1622 The first thing to do is to start tinc with a high debug level in the foreground,
1623 so you can directly see everything tinc logs:
1626 tincd -n @var{netname} -d5 -D
1629 If tinc does not log any error messages, then you might want to check the following things:
1632 @item @file{tinc-up} script
1633 Does this script contain the right commands?
1634 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.
1637 Does the Subnet (or Subnets) in the host configuration file of this host match the portion of the VPN that belongs to this host?
1639 @item Firewalls and NATs
1640 Do you have a firewall or a NAT device (a masquerading firewall or perhaps an ADSL router that performs masquerading)?
1641 If so, check that it allows TCP and UDP traffic on port 655.
1642 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.
1643 You can add @samp{TCPOnly = yes} to your host config file to force tinc to only use a single TCP connection,
1644 this works through most firewalls and NATs. Since version 1.0.10, tinc will automatically fall back to TCP if direct communication via UDP is not possible.
1649 @c ==================================================================
1650 @node Error messages
1651 @section Error messages
1653 What follows is a list of the most common error messages you might find in the logs.
1654 Some of them will only be visible if the debug level is high enough.
1657 @item Could not open /dev/tap0: No such device
1660 @item You forgot to `modprobe netlink_dev' or `modprobe ethertap'.
1661 @item You forgot to compile `Netlink device emulation' in the kernel.
1664 @item Can't write to /dev/net/tun: No such device
1667 @item You forgot to `modprobe tun'.
1668 @item You forgot to compile `Universal TUN/TAP driver' in the kernel.
1669 @item The tun device is located somewhere else in @file{/dev/}.
1672 @item Network address and prefix length do not match!
1675 @item The Subnet field must contain a @emph{network} address, trailing bits should be 0.
1676 @item If you only want to use one IP address, set the netmask to /32.
1679 @item Error reading RSA key file `rsa_key.priv': No such file or directory
1682 @item You forgot to create a public/private keypair.
1683 @item Specify the complete pathname to the private key file with the @samp{PrivateKeyFile} option.
1686 @item Warning: insecure file permissions for RSA private key file `rsa_key.priv'!
1689 @item The private key file is readable by users other than root.
1690 Use chmod to correct the file permissions.
1693 @item Creating metasocket failed: Address family not supported
1696 @item By default tinc tries to create both IPv4 and IPv6 sockets.
1697 On some platforms this might not be implemented.
1698 If the logs show @samp{Ready} later on, then at least one metasocket was created,
1699 and you can ignore this message.
1700 You can add @samp{AddressFamily = ipv4} to @file{tinc.conf} to prevent this from happening.
1703 @item Cannot route packet: unknown IPv4 destination 1.2.3.4
1706 @item You try to send traffic to a host on the VPN for which no Subnet is known.
1707 @item If it is a broadcast address (ending in .255), it probably is a samba server or a Windows host sending broadcast packets.
1711 @item Cannot route packet: ARP request for unknown address 1.2.3.4
1714 @item You try to send traffic to a host on the VPN for which no Subnet is known.
1717 @item Packet with destination 1.2.3.4 is looping back to us!
1720 @item Something is not configured right. Packets are being sent out to the
1721 virtual network device, but according to the Subnet directives in your host configuration
1722 file, those packets should go to your own host. Most common mistake is that
1723 you have a Subnet line in your host configuration file with a prefix length which is
1724 just as large as the prefix of the virtual network interface. The latter should in almost all
1725 cases be larger. Rethink your configuration.
1726 Note that you will only see this message if you specified a debug
1727 level of 5 or higher!
1728 @item Chances are that a @samp{Subnet = ...} line in the host configuration file of this tinc daemon is wrong.
1729 Change it to a subnet that is accepted locally by another interface,
1730 or if that is not the case, try changing the prefix length into /32.
1733 @item Node foo (1.2.3.4) is not reachable
1736 @item Node foo does not have a connection anymore, its tinc daemon is not running or its connection to the Internet is broken.
1739 @item Received UDP packet from unknown source 1.2.3.4 (port 12345)
1742 @item If you see this only sporadically, it is harmless and caused by a node sending packets using an old key.
1745 @item Got bad/bogus/unauthorized REQUEST from foo (1.2.3.4 port 12345)
1748 @item Node foo does not have the right public/private keypair.
1749 Generate new keypairs and distribute them again.
1750 @item An attacker tries to gain access to your VPN.
1751 @item A network error caused corruption of metadata sent from foo.
1756 @c ==================================================================
1757 @node Sending bug reports
1758 @section Sending bug reports
1760 If you really can't find the cause of a problem, or if you suspect tinc is not working right,
1761 you can send us a bugreport, see @ref{Contact information}.
1762 Be sure to include the following information in your bugreport:
1765 @item A clear description of what you are trying to achieve and what the problem is.
1766 @item What platform (operating system, version, hardware architecture) and which version of tinc you use.
1767 @item If compiling tinc fails, a copy of @file{config.log} and the error messages you get.
1768 @item Otherwise, a copy of @file{tinc.conf}, @file{tinc-up} and all files in the @file{hosts/} directory.
1769 @item The output of the commands @samp{ifconfig -a} and @samp{route -n} (or @samp{netstat -rn} if that doesn't work).
1770 @item The output of any command that fails to work as it should (like ping or traceroute).
1773 @c ==================================================================
1774 @node Technical information
1775 @chapter Technical information
1780 * The meta-protocol::
1785 @c ==================================================================
1786 @node The connection
1787 @section The connection
1790 Tinc is a daemon that takes VPN data and transmit that to another host
1791 computer over the existing Internet infrastructure.
1795 * The meta-connection::
1799 @c ==================================================================
1800 @node The UDP tunnel
1801 @subsection The UDP tunnel
1803 @cindex virtual network device
1805 The data itself is read from a character device file, the so-called
1806 @emph{virtual network device}. This device is associated with a network
1807 interface. Any data sent to this interface can be read from the device,
1808 and any data written to the device gets sent from the interface.
1809 There are two possible types of virtual network devices:
1810 `tun' style, which are point-to-point devices which can only handle IPv4 and/or IPv6 packets,
1811 and `tap' style, which are Ethernet devices and handle complete Ethernet frames.
1813 So when tinc reads an Ethernet frame from the device, it determines its
1814 type. When tinc is in it's default routing mode, it can handle IPv4 and IPv6
1815 packets. Depending on the Subnet lines, it will send the packets off to their destination IP address.
1816 In the `switch' and `hub' mode, tinc will use broadcasts and MAC address discovery
1817 to deduce the destination of the packets.
1818 Since the latter modes only depend on the link layer information,
1819 any protocol that runs over Ethernet is supported (for instance IPX and Appletalk).
1820 However, only `tap' style devices provide this information.
1822 After the destination has been determined,
1823 the packet will be compressed (optionally),
1824 a sequence number will be added to the packet,
1825 the packet will then be encrypted
1826 and a message authentication code will be appended.
1828 @cindex encapsulating
1830 When that is done, time has come to actually transport the
1831 packet to the destination computer. We do this by sending the packet
1832 over an UDP connection to the destination host. This is called
1833 @emph{encapsulating}, the VPN packet (though now encrypted) is
1834 encapsulated in another IP datagram.
1836 When the destination receives this packet, the same thing happens, only
1837 in reverse. So it checks the message authentication code, decrypts the contents of the UDP datagram,
1838 checks the sequence number
1839 and writes the decrypted information to its own virtual network device.
1841 If the virtual network device is a `tun' device (a point-to-point tunnel),
1842 there is no problem for the kernel to accept a packet.
1843 However, if it is a `tap' device (this is the only available type on FreeBSD),
1844 the destination MAC address must match that of the virtual network interface.
1845 If tinc is in it's default routing mode, ARP does not work, so the correct destination MAC
1846 can not be known by the sending host.
1847 Tinc solves this by letting the receiving end detect the MAC address of its own virtual network interface
1848 and overwriting the destination MAC address of the received packet.
1850 In switch or hub modes ARP does work so the sender already knows the correct destination MAC address.
1851 In those modes every interface should have a unique MAC address, so make sure they are not the same.
1852 Because switch and hub modes rely on MAC addresses to function correctly,
1853 these modes cannot be used on the following operating systems which don't have a `tap' style virtual network device:
1854 OpenBSD, NetBSD, Darwin and Solaris.
1857 @c ==================================================================
1858 @node The meta-connection
1859 @subsection The meta-connection
1861 Having only a UDP connection available is not enough. Though suitable
1862 for transmitting data, we want to be able to reliably send other
1863 information, such as routing and session key information to somebody.
1866 TCP is a better alternative, because it already contains protection
1867 against information being lost, unlike UDP.
1869 So we establish two connections. One for the encrypted VPN data, and one
1870 for other information, the meta-data. Hence, we call the second
1871 connection the meta-connection. We can now be sure that the
1872 meta-information doesn't get lost on the way to another computer.
1874 @cindex data-protocol
1875 @cindex meta-protocol
1876 Like with any communication, we must have a protocol, so that everybody
1877 knows what everything stands for, and how she should react. Because we
1878 have two connections, we also have two protocols. The protocol used for
1879 the UDP data is the ``data-protocol,'' the other one is the
1882 The reason we don't use TCP for both protocols is that UDP is much
1883 better for encapsulation, even while it is less reliable. The real
1884 problem is that when TCP would be used to encapsulate a TCP stream
1885 that's on the private network, for every packet sent there would be
1886 three ACKs sent instead of just one. Furthermore, if there would be
1887 a timeout, both TCP streams would sense the timeout, and both would
1888 start re-sending packets.
1891 @c ==================================================================
1892 @node The meta-protocol
1893 @section The meta-protocol
1895 The meta protocol is used to tie all tinc daemons together, and
1896 exchange information about which tinc daemon serves which virtual
1899 The meta protocol consists of requests that can be sent to the other
1900 side. Each request has a unique number and several parameters. All
1901 requests are represented in the standard ASCII character set. It is
1902 possible to use tools such as telnet or netcat to connect to a tinc
1903 daemon started with the --bypass-security option
1904 and to read and write requests by hand, provided that one
1905 understands the numeric codes sent.
1907 The authentication scheme is described in @ref{Authentication protocol}. After a
1908 successful authentication, the server and the client will exchange all the
1909 information about other tinc daemons and subnets they know of, so that both
1910 sides (and all the other tinc daemons behind them) have their information
1917 ------------------------------------------------------------------
1918 ADD_EDGE node1 node2 21.32.43.54 655 222 0
1919 | | | | | +-> options
1920 | | | | +----> weight
1921 | | | +--------> UDP port of node2
1922 | | +----------------> real address of node2
1923 | +-------------------------> name of destination node
1924 +-------------------------------> name of source node
1926 ADD_SUBNET node 192.168.1.0/24
1927 | | +--> prefixlength
1928 | +--------> network address
1929 +------------------> owner of this subnet
1930 ------------------------------------------------------------------
1933 The ADD_EDGE messages are to inform other tinc daemons that a connection between
1934 two nodes exist. The address of the destination node is available so that
1935 VPN packets can be sent directly to that node.
1937 The ADD_SUBNET messages inform other tinc daemons that certain subnets belong
1938 to certain nodes. tinc will use it to determine to which node a VPN packet has
1945 ------------------------------------------------------------------
1946 DEL_EDGE node1 node2
1947 | +----> name of destination node
1948 +----------> name of source node
1950 DEL_SUBNET node 192.168.1.0/24
1951 | | +--> prefixlength
1952 | +--------> network address
1953 +------------------> owner of this subnet
1954 ------------------------------------------------------------------
1957 In case a connection between two daemons is closed or broken, DEL_EDGE messages
1958 are sent to inform the other daemons of that fact. Each daemon will calculate a
1959 new route to the the daemons, or mark them unreachable if there isn't any.
1966 ------------------------------------------------------------------
1967 REQ_KEY origin destination
1968 | +--> name of the tinc daemon it wants the key from
1969 +----------> name of the daemon that wants the key
1971 ANS_KEY origin destination 4ae0b0a82d6e0078 91 64 4
1972 | | \______________/ | | +--> MAC length
1973 | | | | +-----> digest algorithm
1974 | | | +--------> cipher algorithm
1975 | | +--> 128 bits key
1976 | +--> name of the daemon that wants the key
1977 +----------> name of the daemon that uses this key
1980 +--> daemon that has changed it's packet key
1981 ------------------------------------------------------------------
1984 The keys used to encrypt VPN packets are not sent out directly. This is
1985 because it would generate a lot of traffic on VPNs with many daemons, and
1986 chances are that not every tinc daemon will ever send a packet to every
1987 other daemon. Instead, if a daemon needs a key it sends a request for it
1988 via the meta connection of the nearest hop in the direction of the
1995 ------------------------------------------------------------------
1998 ------------------------------------------------------------------
2001 There is also a mechanism to check if hosts are still alive. Since network
2002 failures or a crash can cause a daemon to be killed without properly
2003 shutting down the TCP connection, this is necessary to keep an up to date
2004 connection list. PINGs are sent at regular intervals, except when there
2005 is also some other traffic. A little bit of salt (random data) is added
2006 with each PING and PONG message, to make sure that long sequences of PING/PONG
2007 messages without any other traffic won't result in known plaintext.
2009 This basically covers what is sent over the meta connection by tinc.
2012 @c ==================================================================
2018 Tinc got its name from ``TINC,'' short for @emph{There Is No Cabal}; the
2019 alleged Cabal was/is an organisation that was said to keep an eye on the
2020 entire Internet. As this is exactly what you @emph{don't} want, we named
2021 the tinc project after TINC.
2024 But in order to be ``immune'' to eavesdropping, you'll have to encrypt
2025 your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does
2026 exactly that: encrypt.
2027 Tinc by default uses blowfish encryption with 128 bit keys in CBC mode, 32 bit
2028 sequence numbers and 4 byte long message authentication codes to make sure
2029 eavesdroppers cannot get and cannot change any information at all from the
2030 packets they can intercept. The encryption algorithm and message authentication
2031 algorithm can be changed in the configuration. The length of the message
2032 authentication codes is also adjustable. The length of the key for the
2033 encryption algorithm is always the default length used by OpenSSL.
2036 * Authentication protocol::
2037 * Encryption of network packets::
2042 @c ==================================================================
2043 @node Authentication protocol
2044 @subsection Authentication protocol
2046 @cindex authentication
2047 A new scheme for authentication in tinc has been devised, which offers some
2048 improvements over the protocol used in 1.0pre2 and 1.0pre3. Explanation is
2058 --------------------------------------------------------------------------
2059 client <attempts connection>
2061 server <accepts connection>
2065 +-------> name of tinc daemon
2069 +-------> name of tinc daemon
2071 client META_KEY 5f0823a93e35b69e...7086ec7866ce582b
2072 \_________________________________/
2073 +-> RSAKEYLEN bits totally random string S1,
2074 encrypted with server's public RSA key
2076 server META_KEY 6ab9c1640388f8f0...45d1a07f8a672630
2077 \_________________________________/
2078 +-> RSAKEYLEN bits totally random string S2,
2079 encrypted with client's public RSA key
2082 - the client will symmetrically encrypt outgoing traffic using S1
2083 - the server will symmetrically encrypt outgoing traffic using S2
2085 client CHALLENGE da02add1817c1920989ba6ae2a49cecbda0
2086 \_________________________________/
2087 +-> CHALLEN bits totally random string H1
2089 server CHALLENGE 57fb4b2ccd70d6bb35a64c142f47e61d57f
2090 \_________________________________/
2091 +-> CHALLEN bits totally random string H2
2093 client CHAL_REPLY 816a86
2094 +-> 160 bits SHA1 of H2
2096 server CHAL_REPLY 928ffe
2097 +-> 160 bits SHA1 of H1
2099 After the correct challenge replies are received, both ends have proved
2100 their identity. Further information is exchanged.
2102 client ACK 655 123 0
2104 | +----> estimated weight
2105 +--------> listening port of client
2107 server ACK 655 321 0
2109 | +----> estimated weight
2110 +--------> listening port of server
2111 --------------------------------------------------------------------------
2114 This new scheme has several improvements, both in efficiency and security.
2116 First of all, the server sends exactly the same kind of messages over the wire
2117 as the client. The previous versions of tinc first authenticated the client,
2118 and then the server. This scheme even allows both sides to send their messages
2119 simultaneously, there is no need to wait for the other to send something first.
2120 This means that any calculations that need to be done upon sending or receiving
2121 a message can also be done in parallel. This is especially important when doing
2122 RSA encryption/decryption. Given that these calculations are the main part of
2123 the CPU time spent for the authentication, speed is improved by a factor 2.
2125 Second, only one RSA encrypted message is sent instead of two. This reduces the
2126 amount of information attackers can see (and thus use for a cryptographic
2127 attack). It also improves speed by a factor two, making the total speedup a
2130 Third, and most important:
2131 The symmetric cipher keys are exchanged first, the challenge is done
2132 afterwards. In the previous authentication scheme, because a man-in-the-middle
2133 could pass the challenge/chal_reply phase (by just copying the messages between
2134 the two real tinc daemons), but no information was exchanged that was really
2135 needed to read the rest of the messages, the challenge/chal_reply phase was of
2136 no real use. The man-in-the-middle was only stopped by the fact that only after
2137 the ACK messages were encrypted with the symmetric cipher. Potentially, it
2138 could even send it's own symmetric key to the server (if it knew the server's
2139 public key) and read some of the metadata the server would send it (it was
2140 impossible for the mitm to read actual network packets though). The new scheme
2141 however prevents this.
2143 This new scheme makes sure that first of all, symmetric keys are exchanged. The
2144 rest of the messages are then encrypted with the symmetric cipher. Then, each
2145 side can only read received messages if they have their private key. The
2146 challenge is there to let the other side know that the private key is really
2147 known, because a challenge reply can only be sent back if the challenge is
2148 decrypted correctly, and that can only be done with knowledge of the private
2151 Fourth: the first thing that is sent via the symmetric cipher encrypted
2152 connection is a totally random string, so that there is no known plaintext (for
2153 an attacker) in the beginning of the encrypted stream.
2156 @c ==================================================================
2157 @node Encryption of network packets
2158 @subsection Encryption of network packets
2161 A data packet can only be sent if the encryption key is known to both
2162 parties, and the connection is activated. If the encryption key is not
2163 known, a request is sent to the destination using the meta connection
2164 to retrieve it. The packet is stored in a queue while waiting for the
2168 The UDP packet containing the network packet from the VPN has the following layout:
2171 ... | IP header | UDP header | seqno | VPN packet | MAC | UDP trailer
2172 \___________________/\_____/
2174 V +---> digest algorithm
2175 Encrypted with symmetric cipher
2178 So, the entire VPN packet is encrypted using a symmetric cipher, including a 32 bits
2179 sequence number that is added in front of the actual VPN packet, to act as a unique
2180 IV for each packet and to prevent replay attacks. A message authentication code
2181 is added to the UDP packet to prevent alteration of packets. By default the
2182 first 4 bytes of the digest are used for this, but this can be changed using
2183 the MACLength configuration variable.
2185 @c ==================================================================
2186 @node Security issues
2187 @subsection Security issues
2189 In August 2000, we discovered the existence of a security hole in all versions
2190 of tinc up to and including 1.0pre2. This had to do with the way we exchanged
2191 keys. Since then, we have been working on a new authentication scheme to make
2192 tinc as secure as possible. The current version uses the OpenSSL library and
2193 uses strong authentication with RSA keys.
2195 On the 29th of December 2001, Jerome Etienne posted a security analysis of tinc
2196 1.0pre4. Due to a lack of sequence numbers and a message authentication code
2197 for each packet, an attacker could possibly disrupt certain network services or
2198 launch a denial of service attack by replaying intercepted packets. The current
2199 version adds sequence numbers and message authentication codes to prevent such
2202 On the 15th of September 2003, Peter Gutmann posted a security analysis of tinc
2203 1.0.1. He argues that the 32 bit sequence number used by tinc is not a good IV,
2204 that tinc's default length of 4 bytes for the MAC is too short, and he doesn't
2205 like tinc's use of RSA during authentication. We do not know of a security hole
2206 in this version of tinc, but tinc's security is not as strong as TLS or IPsec.
2207 We will address these issues in tinc 2.0.
2209 Cryptography is a hard thing to get right. We cannot make any
2210 guarantees. Time, review and feedback are the only things that can
2211 prove the security of any cryptographic product. If you wish to review
2212 tinc or give us feedback, you are stronly encouraged to do so.
2215 @c ==================================================================
2216 @node Platform specific information
2217 @chapter Platform specific information
2220 * Interface configuration::
2224 @c ==================================================================
2225 @node Interface configuration
2226 @section Interface configuration
2228 When configuring an interface, one normally assigns it an address and a
2229 netmask. The address uniquely identifies the host on the network attached to
2230 the interface. The netmask, combined with the address, forms a subnet. It is
2231 used to add a route to the routing table instructing the kernel to send all
2232 packets which fall into that subnet to that interface. Because all packets for
2233 the entire VPN should go to the virtual network interface used by tinc, the
2234 netmask should be such that it encompasses the entire VPN.
2238 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2240 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2241 @item Linux iproute2
2242 @tab @code{ip addr add} @var{address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2244 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2246 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2248 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2250 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2251 @item Darwin (MacOS/X)
2252 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2254 @tab @code{netsh interface ip set address} @var{interface} @code{static} @var{address} @var{netmask}
2260 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2262 @tab @code{ifconfig} @var{interface} @code{add} @var{address}@code{/}@var{prefixlength}
2264 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2266 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2268 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2270 @tab @code{ifconfig} @var{interface} @code{inet6 plumb up}
2272 @tab @code{ifconfig} @var{interface} @code{inet6 addif} @var{address} @var{address}
2273 @item Darwin (MacOS/X)
2274 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2276 @tab @code{netsh interface ipv6 add address} @var{interface} @code{static} @var{address}/@var{prefixlength}
2280 @c ==================================================================
2284 In some cases it might be necessary to add more routes to the virtual network
2285 interface. There are two ways to indicate which interface a packet should go
2286 to, one is to use the name of the interface itself, another way is to specify
2287 the (local) address that is assigned to that interface (@var{local_address}). The
2288 former way is unambiguous and therefore preferable, but not all platforms
2291 Adding routes to IPv4 subnets:
2293 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2295 @tab @code{route add -net} @var{network_address} @code{netmask} @var{netmask} @var{interface}
2296 @item Linux iproute2
2297 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2299 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2301 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2303 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2305 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
2306 @item Darwin (MacOS/X)
2307 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2309 @tab @code{netsh routing ip add persistentroute} @var{network_address} @var{netmask} @var{interface} @var{local_address}
2312 Adding routes to IPv6 subnets:
2314 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2316 @tab @code{route add -A inet6} @var{network_address}@code{/}@var{prefixlength} @var{interface}
2317 @item Linux iproute2
2318 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2320 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2322 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
2324 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
2326 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
2327 @item Darwin (MacOS/X)
2330 @tab @code{netsh interface ipv6 add route} @var{network address}/@var{prefixlength} @var{interface}
2334 @c ==================================================================
2340 * Contact information::
2345 @c ==================================================================
2346 @node Contact information
2347 @section Contact information
2350 Tinc's website is at @url{http://www.tinc-vpn.org/},
2351 this server is located in the Netherlands.
2354 We have an IRC channel on the FreeNode and OFTC IRC networks. Connect to
2355 @uref{http://www.freenode.net/, irc.freenode.net}
2357 @uref{http://www.oftc.net/, irc.oftc.net}
2358 and join channel #tinc.
2361 @c ==================================================================
2366 @item Ivo Timmermans (zarq)
2367 @item Guus Sliepen (guus) (@email{guus@@tinc-vpn.org})
2370 We have received a lot of valuable input from users. With their help,
2371 tinc has become the flexible and robust tool that it is today. We have
2372 composed a list of contributions, in the file called @file{THANKS} in
2373 the source distribution.
2376 @c ==================================================================
2378 @unnumbered Concept Index
2380 @c ==================================================================
2384 @c ==================================================================