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{} 1998-2013 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{} 1998-2013 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 ==================================================================
69 * Technical information::
70 * Platform specific information::
72 * Concept Index:: All used terms explained
76 @c ==================================================================
81 Tinc is a Virtual Private Network (VPN) daemon that uses tunneling and
82 encryption to create a secure private network between hosts on the
85 Because the tunnel appears to the IP level network code as a normal
86 network device, there is no need to adapt any existing software.
87 The encrypted tunnels allows VPN sites to share information with each other
88 over the Internet without exposing any information to others.
90 This document is the manual for tinc. Included are chapters on how to
91 configure your computer to use tinc, as well as the configuration
92 process of tinc itself.
95 * Virtual Private Networks::
97 * Supported platforms::
100 @c ==================================================================
101 @node Virtual Private Networks
102 @section Virtual Private Networks
105 A Virtual Private Network or VPN is a network that can only be accessed
106 by a few elected computers that participate. This goal is achievable in
107 more than just one way.
110 Private networks can consist of a single stand-alone Ethernet LAN. Or
111 even two computers hooked up using a null-modem cable. In these cases,
113 obvious that the network is @emph{private}, no one can access it from the
114 outside. But if your computers are linked to the Internet, the network
115 is not private anymore, unless one uses firewalls to block all private
116 traffic. But then, there is no way to send private data to trusted
117 computers on the other end of the Internet.
120 This problem can be solved by using @emph{virtual} networks. Virtual
121 networks can live on top of other networks, but they use encapsulation to
122 keep using their private address space so they do not interfere with
123 the Internet. Mostly, virtual networks appear like a single LAN, even though
124 they can span the entire world. But virtual networks can't be secured
125 by using firewalls, because the traffic that flows through it has to go
126 through the Internet, where other people can look at it.
128 As is the case with either type of VPN, anybody could eavesdrop. Or
129 worse, alter data. Hence it's probably advisable to encrypt the data
130 that flows over the network.
132 When one introduces encryption, we can form a true VPN. Other people may
133 see encrypted traffic, but if they don't know how to decipher it (they
134 need to know the key for that), they cannot read the information that flows
135 through the VPN. This is what tinc was made for.
138 @c ==================================================================
143 I really don't quite remember what got us started, but it must have been
144 Guus' idea. He wrote a simple implementation (about 50 lines of C) that
145 used the ethertap device that Linux knows of since somewhere
146 about kernel 2.1.60. It didn't work immediately and he improved it a
147 bit. At this stage, the project was still simply called "vpnd".
149 Since then, a lot has changed---to say the least.
152 Tinc now supports encryption, it consists of a single daemon (tincd) for
153 both the receiving and sending end, it has become largely
154 runtime-configurable---in short, it has become a full-fledged
155 professional package.
157 @cindex traditional VPNs
159 Tinc also allows more than two sites to connect to eachother and form a single VPN.
160 Traditionally VPNs are created by making tunnels, which only have two endpoints.
161 Larger VPNs with more sites are created by adding more tunnels.
162 Tinc takes another approach: only endpoints are specified,
163 the software itself will take care of creating the tunnels.
164 This allows for easier configuration and improved scalability.
166 A lot can---and will be---changed. We have a number of things that we would like to
167 see in the future releases of tinc. Not everything will be available in
168 the near future. Our first objective is to make tinc work perfectly as
169 it stands, and then add more advanced features.
171 Meanwhile, we're always open-minded towards new ideas. And we're
175 @c ==================================================================
176 @node Supported platforms
177 @section Supported platforms
180 Tinc has been verified to work under Linux, FreeBSD, OpenBSD, NetBSD, MacOS/X (Darwin), Solaris, and Windows (both natively and in a Cygwin environment),
181 with various hardware architectures. These are some of the platforms
182 that are supported by the universal tun/tap device driver or other virtual network device drivers.
183 Without such a driver, tinc will most
184 likely compile and run, but it will not be able to send or receive data
188 For an up to date list of supported platforms, please check the list on
190 @uref{http://www.tinc-vpn.org/platforms/}.
198 @c Preparing your system
205 @c ==================================================================
207 @chapter Preparations
209 This chapter contains information on how to prepare your system to
213 * Configuring the kernel::
218 @c ==================================================================
219 @node Configuring the kernel
220 @section Configuring the kernel
223 * Configuration of Linux kernels::
224 * Configuration of FreeBSD kernels::
225 * Configuration of OpenBSD kernels::
226 * Configuration of NetBSD kernels::
227 * Configuration of Solaris kernels::
228 * Configuration of Darwin (MacOS/X) kernels::
229 * Configuration of Windows::
233 @c ==================================================================
234 @node Configuration of Linux kernels
235 @subsection Configuration of Linux kernels
237 @cindex Universal tun/tap
238 For tinc to work, you need a kernel that supports the Universal tun/tap device.
239 Most distributions come with kernels that already support this.
240 Here are the options you have to turn on when configuring a new kernel:
243 Code maturity level options
244 [*] Prompt for development and/or incomplete code/drivers
245 Network device support
246 <M> Universal tun/tap device driver support
249 It's not necessary to compile this driver as a module, even if you are going to
250 run more than one instance of tinc.
252 If you decide to build the tun/tap driver as a kernel module, add these lines
253 to @file{/etc/modules.conf}:
256 alias char-major-10-200 tun
260 @c ==================================================================
261 @node Configuration of FreeBSD kernels
262 @subsection Configuration of FreeBSD kernels
264 For FreeBSD version 4.1 and higher, tun and tap drivers are included in the default kernel configuration.
265 The tap driver can be loaded with @code{kldload if_tap}, or by adding @code{if_tap_load="YES"} to @file{/boot/loader.conf}.
268 @c ==================================================================
269 @node Configuration of OpenBSD kernels
270 @subsection Configuration of OpenBSD kernels
272 For OpenBSD version 2.9 and higher,
273 the tun driver is included in the default kernel configuration.
274 There is also a kernel patch from @uref{http://diehard.n-r-g.com/stuff/openbsd/}
275 which adds a tap device to OpenBSD which should work with tinc,
276 but with recent versions of OpenBSD,
277 a tun device can act as a tap device by setting the link0 option with ifconfig.
280 @c ==================================================================
281 @node Configuration of NetBSD kernels
282 @subsection Configuration of NetBSD kernels
284 For NetBSD version 1.5.2 and higher,
285 the tun driver is included in the default kernel configuration.
287 Tunneling IPv6 may not work on NetBSD's tun device.
290 @c ==================================================================
291 @node Configuration of Solaris kernels
292 @subsection Configuration of Solaris kernels
294 For Solaris 8 (SunOS 5.8) and higher,
295 the tun driver may or may not be included in the default kernel configuration.
296 If it isn't, the source can be downloaded from @uref{http://vtun.sourceforge.net/tun/}.
297 For x86 and sparc64 architectures, precompiled versions can be found at @uref{http://www.monkey.org/~dugsong/fragroute/}.
298 If the @file{net/if_tun.h} header file is missing, install it from the source package.
301 @c ==================================================================
302 @node Configuration of Darwin (MacOS/X) kernels
303 @subsection Configuration of Darwin (MacOS/X) kernels
305 Tinc on Darwin relies on a tunnel driver for its data acquisition from the kernel.
306 Tinc supports either the driver from @uref{http://tuntaposx.sourceforge.net/},
307 which supports both tun and tap style devices,
308 and also the driver from from @uref{http://chrisp.de/en/projects/tunnel.html}.
309 The former driver is recommended.
310 The tunnel driver must be loaded before starting tinc with the following command:
317 @c ==================================================================
318 @node Configuration of Windows
319 @subsection Configuration of Windows
321 You will need to install the latest TAP-Win32 driver from OpenVPN.
322 You can download it from @uref{http://openvpn.sourceforge.net}.
323 Using the Network Connections control panel,
324 configure the TAP-Win32 network interface in the same way as you would do from the tinc-up script,
325 as explained in the rest of the documentation.
328 @c ==================================================================
334 Before you can configure or build tinc, you need to have the OpenSSL,
335 zlib and lzo libraries installed on your system. If you try to configure tinc without
336 having them installed, configure will give you an error message, and stop.
347 @c ==================================================================
352 For all cryptography-related functions, tinc uses the functions provided
353 by the OpenSSL library.
355 If this library is not installed, you wil get an error when configuring
356 tinc for build. Support for running tinc with other cryptographic libraries
357 installed @emph{may} be added in the future.
359 You can use your operating system's package manager to install this if
360 available. Make sure you install the development AND runtime versions
363 If you have to install OpenSSL manually, you can get the source code
364 from @url{http://www.openssl.org/}. Instructions on how to configure,
365 build and install this package are included within the package. Please
366 make sure you build development and runtime libraries (which is the
369 If you installed the OpenSSL libraries from source, it may be necessary
370 to let configure know where they are, by passing configure one of the
371 --with-openssl-* parameters.
374 --with-openssl=DIR OpenSSL library and headers prefix
375 --with-openssl-include=DIR OpenSSL headers directory
376 (Default is OPENSSL_DIR/include)
377 --with-openssl-lib=DIR OpenSSL library directory
378 (Default is OPENSSL_DIR/lib)
382 @subsubheading License
385 The complete source code of tinc is covered by the GNU GPL version 2.
386 Since the license under which OpenSSL is distributed is not directly
387 compatible with the terms of the GNU GPL
388 @uref{http://www.openssl.org/support/faq.html#LEGAL2}, we
389 include an exemption to the GPL (see also the file COPYING.README) to allow
390 everyone to create a statically or dynamically linked executable:
393 This program is released under the GPL with the additional exemption
394 that compiling, linking, and/or using OpenSSL is allowed. You may
395 provide binary packages linked to the OpenSSL libraries, provided that
396 all other requirements of the GPL are met.
399 Since the LZO library used by tinc is also covered by the GPL,
400 we also present the following exemption:
403 Hereby I grant a special exception to the tinc VPN project
404 (http://www.tinc-vpn.org/) to link the LZO library with the OpenSSL library
405 (http://www.openssl.org).
407 Markus F.X.J. Oberhumer
411 @c ==================================================================
416 For the optional compression of UDP packets, tinc uses the functions provided
419 If this library is not installed, you wil get an error when running the
420 configure script. You can either install the zlib library, or disable support
421 for zlib compression by using the "--disable-zlib" option when running the
422 configure script. Note that if you disable support for zlib, the resulting
423 binary will not work correctly on VPNs where zlib compression is used.
425 You can use your operating system's package manager to install this if
426 available. Make sure you install the development AND runtime versions
429 If you have to install zlib manually, you can get the source code
430 from @url{http://www.gzip.org/zlib/}. Instructions on how to configure,
431 build and install this package are included within the package. Please
432 make sure you build development and runtime libraries (which is the
436 @c ==================================================================
441 Another form of compression is offered using the LZO library.
443 If this library is not installed, you wil get an error when running the
444 configure script. You can either install the LZO library, or disable support
445 for LZO compression by using the "--disable-lzo" option when running the
446 configure script. Note that if you disable support for LZO, the resulting
447 binary will not work correctly on VPNs where LZO compression is used.
449 You can use your operating system's package manager to install this if
450 available. Make sure you install the development AND runtime versions
453 If you have to install lzo manually, you can get the source code
454 from @url{http://www.oberhumer.com/opensource/lzo/}. Instructions on how to configure,
455 build and install this package are included within the package. Please
456 make sure you build development and runtime libraries (which is the
460 @c ==================================================================
462 @subsection libcurses
465 For the "tincctl top" command, tinc requires a curses library.
467 If this library is not installed, you wil get an error when running the
468 configure script. You can either install a suitable curses library, or disable
469 all functionality that depends on a curses library by using the
470 "--disable-curses" option when running the configure script.
472 There are several curses libraries. It is recommended that you install
473 "ncurses" (@url{http://invisible-island.net/ncurses/}),
474 however other curses libraries should also work.
475 In particular, "PDCurses" (@url{http://pdcurses.sourceforge.net/})
476 is recommended if you want to compile tinc for Windows.
478 You can use your operating system's package manager to install this if
479 available. Make sure you install the development AND runtime versions
483 @c ==================================================================
485 @subsection libreadline
488 For the "tincctl" command's shell functionality, tinc uses the readline library.
490 If this library is not installed, you wil get an error when running the
491 configure script. You can either install a suitable readline library, or
492 disable all functionality that depends on a readline library by using the
493 "--disable-readline" option when running the configure script.
495 You can use your operating system's package manager to install this if
496 available. Make sure you install the development AND runtime versions
499 If you have to install libreadline manually, you can get the source code from
500 @url{http://www.gnu.org/software/readline/}. Instructions on how to configure,
501 build and install this package are included within the package. Please make
502 sure you build development and runtime libraries (which is the default).
514 @c ==================================================================
516 @chapter Installation
518 If you use Debian, you may want to install one of the
519 precompiled packages for your system. These packages are equipped with
520 system startup scripts and sample configurations.
522 If you cannot use one of the precompiled packages, or you want to compile tinc
523 for yourself, you can use the source. The source is distributed under
524 the GNU General Public License (GPL). Download the source from the
525 @uref{http://www.tinc-vpn.org/download/, download page}, which has
526 the checksums of these files listed; you may wish to check these with
527 md5sum before continuing.
529 Tinc comes in a convenient autoconf/automake package, which you can just
530 treat the same as any other package. Which is just untar it, type
531 `./configure' and then `make'.
532 More detailed instructions are in the file @file{INSTALL}, which is
533 included in the source distribution.
536 * Building and installing tinc::
541 @c ==================================================================
542 @node Building and installing tinc
543 @section Building and installing tinc
545 Detailed instructions on configuring the source, building tinc and installing tinc
546 can be found in the file called @file{INSTALL}.
548 @cindex binary package
549 If you happen to have a binary package for tinc for your distribution,
550 you can use the package management tools of that distribution to install tinc.
551 The documentation that comes along with your distribution will tell you how to do that.
554 * Darwin (MacOS/X) build environment::
555 * Cygwin (Windows) build environment::
556 * MinGW (Windows) build environment::
560 @c ==================================================================
561 @node Darwin (MacOS/X) build environment
562 @subsection Darwin (MacOS/X) build environment
564 In order to build tinc on Darwin, you need to install the MacOS/X Developer Tools
565 from @uref{http://developer.apple.com/tools/macosxtools.html} and
566 a recent version of Fink from @uref{http://www.finkproject.org/}.
568 After installation use fink to download and install the following packages:
569 autoconf25, automake, dlcompat, m4, openssl, zlib and lzo.
571 @c ==================================================================
572 @node Cygwin (Windows) build environment
573 @subsection Cygwin (Windows) build environment
575 If Cygwin hasn't already been installed, install it directly from
576 @uref{http://www.cygwin.com/}.
578 When tinc is compiled in a Cygwin environment, it can only be run in this environment,
579 but all programs, including those started outside the Cygwin environment, will be able to use the VPN.
580 It will also support all features.
582 @c ==================================================================
583 @node MinGW (Windows) build environment
584 @subsection MinGW (Windows) build environment
586 You will need to install the MinGW environment from @uref{http://www.mingw.org}.
588 When tinc is compiled using MinGW it runs natively under Windows,
589 it is not necessary to keep MinGW installed.
591 When detaching, tinc will install itself as a service,
592 which will be restarted automatically after reboots.
595 @c ==================================================================
597 @section System files
599 Before you can run tinc, you must make sure you have all the needed
600 files on your system.
608 @c ==================================================================
610 @subsection Device files
613 Most operating systems nowadays come with the necessary device files by default,
614 or they have a mechanism to create them on demand.
616 If you use Linux and do not have udev installed,
617 you may need to create the following device file if it does not exist:
620 mknod -m 600 /dev/net/tun c 10 200
624 @c ==================================================================
626 @subsection Other files
628 @subsubheading @file{/etc/networks}
630 You may add a line to @file{/etc/networks} so that your VPN will get a
631 symbolic name. For example:
637 @subsubheading @file{/etc/services}
640 You may add this line to @file{/etc/services}. The effect is that you
641 may supply a @samp{tinc} as a valid port number to some programs. The
642 number 655 is registered with the IANA.
647 # Ivo Timmermans <ivo@@tinc-vpn.org>
662 @c ==================================================================
664 @chapter Configuration
667 * Configuration introduction::
668 * Multiple networks::
669 * How connections work::
670 * Configuration files::
671 * Network interfaces::
672 * Example configuration::
675 @c ==================================================================
676 @node Configuration introduction
677 @section Configuration introduction
679 Before actually starting to configure tinc and editing files,
680 make sure you have read this entire section so you know what to expect.
681 Then, make it clear to yourself how you want to organize your VPN:
682 What are the nodes (computers running tinc)?
683 What IP addresses/subnets do they have?
684 What is the network mask of the entire VPN?
685 Do you need special firewall rules?
686 Do you have to set up masquerading or forwarding rules?
687 Do you want to run tinc in router mode or switch mode?
688 These questions can only be answered by yourself,
689 you will not find the answers in this documentation.
690 Make sure you have an adequate understanding of networks in general.
691 @cindex Network Administrators Guide
692 A good resource on networking is the
693 @uref{http://www.tldp.org/LDP/nag2/, Linux Network Administrators Guide}.
695 If you have everything clearly pictured in your mind,
696 proceed in the following order:
697 First, create the initial configuration files and public/private keypairs using the following command:
699 tincctl -n @var{NETNAME} init @var{NAME}
701 Second, use @samp{tincctl -n @var{NETNAME} config ...} to further configure tinc.
702 Finally, export your host configuration file using @samp{tincctl -n @var{NETNAME} export} and send it to those
703 people or computers you want tinc to connect to.
704 They should send you their host configuration file back, which you can import using @samp{tincctl -n @var{NETNAME} import}.
706 These steps are described in the subsections below.
709 @c ==================================================================
710 @node Multiple networks
711 @section Multiple networks
713 @cindex multiple networks
716 In order to allow you to run more than one tinc daemon on one computer,
717 for instance if your computer is part of more than one VPN,
718 you can assign a @var{netname} to your VPN.
719 It is not required if you only run one tinc daemon,
720 it doesn't even have to be the same on all the nodes of your VPN,
721 but it is recommended that you choose one anyway.
723 We will asume you use a netname throughout this document.
724 This means that you call tincctl with the -n argument,
725 which will specify the netname.
727 The effect of this option is that tinc will set its configuration
728 root to @file{@value{sysconfdir}/tinc/@var{netname}/}, where @var{netname} is your argument to the -n option.
729 You will also notice that log messages it appears in syslog as coming from @file{tinc.@var{netname}},
730 and on Linux, unless specified otherwise, the name of the virtual network interface will be the same as the network name.
732 However, it is not strictly necessary that you call tinc with the -n
733 option. If you don not use it, the network name will just be empty, and
734 tinc will look for files in @file{@value{sysconfdir}/tinc/} instead of
735 @file{@value{sysconfdir}/tinc/@var{netname}/};
736 the configuration file will then be @file{@value{sysconfdir}/tinc/tinc.conf},
737 and the host configuration files are expected to be in @file{@value{sysconfdir}/tinc/hosts/}.
740 @c ==================================================================
741 @node How connections work
742 @section How connections work
744 When tinc starts up, it parses the command-line options and then
745 reads in the configuration file tinc.conf.
746 If it sees one or more `ConnectTo' values pointing to other tinc daemons in that file,
747 it will try to connect to those other daemons.
748 Whether this succeeds or not and whether `ConnectTo' is specified or not,
749 tinc will listen for incoming connection from other deamons.
750 If you did specify a `ConnectTo' value and the other side is not responding,
751 tinc will keep retrying.
752 This means that once started, tinc will stay running until you tell it to stop,
753 and failures to connect to other tinc daemons will not stop your tinc daemon
754 for trying again later.
755 This means you don't have to intervene if there are temporary network problems.
759 There is no real distinction between a server and a client in tinc.
760 If you wish, you can view a tinc daemon without a `ConnectTo' value as a server,
761 and one which does specify such a value as a client.
762 It does not matter if two tinc daemons have a `ConnectTo' value pointing to each other however.
764 Connections specified using `ConnectTo' are so-called meta-connections.
765 Tinc daemons exchange information about all other daemon they know about via these meta-connections.
766 After learning about all the daemons in the VPN,
767 tinc will create other connections as necessary in order to communicate with them.
768 For example, if there are three daemons named A, B and C, and A has @samp{ConnectTo = B} in its tinc.conf file,
769 and C has @samp{ConnectTo = B} in its tinc.conf file, then A will learn about C from B,
770 and will be able to exchange VPN packets with C without the need to have @samp{ConnectTo = C} in its tinc.conf file.
772 It could be that some daemons are located behind a Network Address Translation (NAT) device, or behind a firewall.
773 In the above scenario with three daemons, if A and C are behind a NAT,
774 B will automatically help A and C punch holes through their NAT,
775 in a way similar to the STUN protocol, so that A and C can still communicate with each other directly.
776 It is not always possible to do this however, and firewalls might also prevent direct communication.
777 In that case, VPN packets between A and C will be forwarded by B.
779 In effect, all nodes in the VPN will be able to talk to each other, as long as
780 their is a path of meta-connections between them, and whenever possible, two
781 nodes will communicate with each other directly.
784 @c ==================================================================
785 @node Configuration files
786 @section Configuration files
788 The actual configuration of the daemon is done in the file
789 @file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf} and at least one other file in the directory
790 @file{@value{sysconfdir}/tinc/@var{netname}/hosts/}.
792 These file consists of comments (lines started with a #) or assignments
799 The variable names are case insensitive, and any spaces, tabs, newlines
800 and carriage returns are ignored. Note: it is not required that you put
801 in the `=' sign, but doing so improves readability. If you leave it
802 out, remember to replace it with at least one space character.
804 The server configuration is complemented with host specific configuration (see
805 the next section). Although all host configuration options for the local node
806 listed in this document can also be put in
807 @file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf}, it is recommended to
808 put host specific configuration options in the host configuration file, as this
809 makes it easy to exchange with other nodes.
811 You can edit the config file manually, but it is recommended that you use
812 tincctl to change configuration variables for you.
814 In the following two subsections all valid variables are listed in alphabetical order.
815 The default value is given between parentheses,
816 other comments are between square brackets.
819 * Main configuration variables::
820 * Host configuration variables::
826 @c ==================================================================
827 @node Main configuration variables
828 @subsection Main configuration variables
831 @cindex AddressFamily
832 @item AddressFamily = <ipv4|ipv6|any> (any)
833 This option affects the address family of listening and outgoing sockets.
834 If any is selected, then depending on the operating system
835 both IPv4 and IPv6 or just IPv6 listening sockets will be created.
838 @item AutoConnect = <count> (0) [experimental]
839 If set to a non-zero value,
840 tinc will try to only have count meta connections to other nodes,
841 by automatically making or breaking connections to known nodes.
842 Higher values increase redundancy but also increase meta data overhead.
843 When using this option, a good value is 3.
845 @cindex BindToAddress
846 @item BindToAddress = <@var{address}> [<@var{port}>]
847 If your computer has more than one IPv4 or IPv6 address, tinc
848 will by default listen on all of them for incoming connections.
849 Multiple BindToAddress variables may be specified,
850 in which case listening sockets for each specified address are made.
852 If no @var{port} is specified, the socket will be bound to the port specified by the Port option,
853 or to port 655 if neither is given.
854 To only bind to a specific port but not to a specific address, use "*" for the @var{address}.
856 @cindex BindToInterface
857 @item BindToInterface = <@var{interface}> [experimental]
858 If you have more than one network interface in your computer, tinc will
859 by default listen on all of them for incoming connections. It is
860 possible to bind tinc to a single interface like eth0 or ppp0 with this
863 This option may not work on all platforms.
864 Also, on some platforms it will not actually bind to an interface,
865 but rather to the address that the interface has at the moment a socket is created.
868 @item Broadcast = <no | mst | direct> (mst) [experimental]
869 This option selects the way broadcast packets are sent to other daemons.
870 @emph{NOTE: all nodes in a VPN must use the same Broadcast mode, otherwise routing loops can form.}
874 Broadcast packets are never sent to other nodes.
877 Broadcast packets are sent and forwarded via the VPN's Minimum Spanning Tree.
878 This ensures broadcast packets reach all nodes.
881 Broadcast packets are sent directly to all nodes that can be reached directly.
882 Broadcast packets received from other nodes are never forwarded.
883 If the IndirectData option is also set, broadcast packets will only be sent to nodes which we have a meta connection to.
887 @item ConnectTo = <@var{name}>
888 Specifies which other tinc daemon to connect to on startup.
889 Multiple ConnectTo variables may be specified,
890 in which case outgoing connections to each specified tinc daemon are made.
891 The names should be known to this tinc daemon
892 (i.e., there should be a host configuration file for the name on the ConnectTo line).
894 If you don't specify a host with ConnectTo,
895 tinc won't try to connect to other daemons at all,
896 and will instead just listen for incoming connections.
899 @item DecrementTTL = <yes | no> (no) [experimental]
900 When enabled, tinc will decrement the Time To Live field in IPv4 packets, or the Hop Limit field in IPv6 packets,
901 before forwarding a received packet to the virtual network device or to another node,
902 and will drop packets that have a TTL value of zero,
903 in which case it will send an ICMP Time Exceeded packet back.
905 Do not use this option if you use switch mode and want to use IPv6.
908 @item Device = <@var{device}> (@file{/dev/tap0}, @file{/dev/net/tun} or other depending on platform)
909 The virtual network device to use.
910 Tinc will automatically detect what kind of device it is.
911 Note that you can only use one device per daemon.
912 Under Windows, use @var{Interface} instead of @var{Device}.
913 Note that you can only use one device per daemon.
914 See also @ref{Device files}.
917 @item DeviceType = <@var{type}> (platform dependent)
918 The type of the virtual network device.
919 Tinc will normally automatically select the right type of tun/tap interface, and this option should not be used.
920 However, this option can be used to select one of the special interface types, if support for them is compiled in.
925 Use a dummy interface.
926 No packets are ever read or written to a virtual network device.
927 Useful for testing, or when setting up a node that only forwards packets for other nodes.
931 Open a raw socket, and bind it to a pre-existing
932 @var{Interface} (eth0 by default).
933 All packets are read from this interface.
934 Packets received for the local node are written to the raw socket.
935 However, at least on Linux, the operating system does not process IP packets destined for the local host.
939 Open a multicast UDP socket and bind it to the address and port (separated by spaces) and optionally a TTL value specified using @var{Device}.
940 Packets are read from and written to this multicast socket.
941 This can be used to connect to UML, QEMU or KVM instances listening on the same multicast address.
942 Do NOT connect multiple tinc daemons to the same multicast address, this will very likely cause routing loops.
943 Also note that this can cause decrypted VPN packets to be sent out on a real network if misconfigured.
946 @item uml (not compiled in by default)
947 Create a UNIX socket with the filename specified by
948 @var{Device}, or @file{@value{localstatedir}/run/@var{netname}.umlsocket}
950 Tinc will wait for a User Mode Linux instance to connect to this socket.
953 @item vde (not compiled in by default)
954 Uses the libvdeplug library to connect to a Virtual Distributed Ethernet switch,
955 using the UNIX socket specified by
956 @var{Device}, or @file{@value{localstatedir}/run/vde.ctl}
960 Also, in case tinc does not seem to correctly interpret packets received from the virtual network device,
961 it can be used to change the way packets are interpreted:
964 @item tun (BSD and Linux)
966 Depending on the platform, this can either be with or without an address family header (see below).
969 @item tunnohead (BSD)
970 Set type to tun without an address family header.
971 Tinc will expect packets read from the virtual network device to start with an IP header.
972 On some platforms IPv6 packets cannot be read from or written to the device in this mode.
975 @item tunifhead (BSD)
976 Set type to tun with an address family header.
977 Tinc will expect packets read from the virtual network device
978 to start with a four byte header containing the address family,
979 followed by an IP header.
980 This mode should support both IPv4 and IPv6 packets.
982 @item tap (BSD and Linux)
984 Tinc will expect packets read from the virtual network device
985 to start with an Ethernet header.
989 @item DirectOnly = <yes|no> (no) [experimental]
990 When this option is enabled, packets that cannot be sent directly to the destination node,
991 but which would have to be forwarded by an intermediate node, are dropped instead.
992 When combined with the IndirectData option,
993 packets for nodes for which we do not have a meta connection with are also dropped.
995 @cindex ECDSAPrivateKeyFile
996 @item ECDSAPrivateKeyFile = <@var{path}> (@file{@value{sysconfdir}/tinc/@var{netname}/ecdsa_key.priv})
997 The file in which the private ECDSA key of this tinc daemon resides.
998 This is only used if ExperimentalProtocol is enabled.
1000 @cindex ExperimentalProtocol
1001 @item ExperimentalProtocol = <yes|no> (no) [experimental]
1002 When this option is enabled, experimental protocol enhancements will be used.
1003 Ephemeral ECDH will be used for key exchanges,
1004 and ECDSA will be used instead of RSA for authentication.
1005 When enabled, an ECDSA key must have been generated before with
1006 @samp{tincctl generate-ecdsa-keys}.
1007 The experimental protocol may change at any time,
1008 and there is no guarantee that tinc will run stable when it is used.
1011 @item Forwarding = <off|internal|kernel> (internal) [experimental]
1012 This option selects the way indirect packets are forwarded.
1016 Incoming packets that are not meant for the local node,
1017 but which should be forwarded to another node, are dropped.
1020 Incoming packets that are meant for another node are forwarded by tinc internally.
1022 This is the default mode, and unless you really know you need another forwarding mode, don't change it.
1025 Incoming packets are always sent to the TUN/TAP device, even if the packets are not for the local node.
1026 This is less efficient, but allows the kernel to apply its routing and firewall rules on them,
1027 and can also help debugging.
1031 @item Hostnames = <yes|no> (no)
1032 This option selects whether IP addresses (both real and on the VPN)
1033 should be resolved. Since DNS lookups are blocking, it might affect
1034 tinc's efficiency, even stopping the daemon for a few seconds everytime
1035 it does a lookup if your DNS server is not responding.
1037 This does not affect resolving hostnames to IP addresses from the
1038 configuration file, but whether hostnames should be resolved while logging.
1041 @item Interface = <@var{interface}>
1042 Defines the name of the interface corresponding to the virtual network device.
1043 Depending on the operating system and the type of device this may or may not actually set the name of the interface.
1044 Under Windows, this variable is used to select which network interface will be used.
1045 If you specified a Device, this variable is almost always already correctly set.
1047 @cindex LocalDiscovery
1048 @item LocalDiscovery = <yes | no> (no)
1049 When enabled, tinc will try to detect peers that are on the same local network.
1050 This will allow direct communication using LAN addresses, even if both peers are behind a NAT
1051 and they only ConnectTo a third node outside the NAT,
1052 which normally would prevent the peers from learning each other's LAN address.
1054 Currently, local discovery is implemented by sending broadcast packets to the LAN during path MTU discovery.
1055 This feature may not work in all possible situations.
1058 @item Mode = <router|switch|hub> (router)
1059 This option selects the way packets are routed to other daemons.
1065 variables in the host configuration files will be used to form a routing table.
1066 Only packets of routable protocols (IPv4 and IPv6) are supported in this mode.
1068 This is the default mode, and unless you really know you need another mode, don't change it.
1072 In this mode the MAC addresses of the packets on the VPN will be used to
1073 dynamically create a routing table just like an Ethernet switch does.
1074 Unicast, multicast and broadcast packets of every protocol that runs over Ethernet are supported in this mode
1075 at the cost of frequent broadcast ARP requests and routing table updates.
1077 This mode is primarily useful if you want to bridge Ethernet segments.
1081 This mode is almost the same as the switch mode, but instead
1082 every packet will be broadcast to the other daemons
1083 while no routing table is managed.
1087 @item KeyExpire = <@var{seconds}> (3600)
1088 This option controls the time the encryption keys used to encrypt the data
1089 are valid. It is common practice to change keys at regular intervals to
1090 make it even harder for crackers, even though it is thought to be nearly
1091 impossible to crack a single key.
1094 @item MACExpire = <@var{seconds}> (600)
1095 This option controls the amount of time MAC addresses are kept before they are removed.
1096 This only has effect when Mode is set to "switch".
1099 @item Name = <@var{name}> [required]
1100 This is a symbolic name for this connection.
1101 The name should consist only of alfanumeric and underscore characters (a-z, A-Z, 0-9 and _), and is case sensitive.
1103 If Name starts with a $, then the contents of the environment variable that follows will be used.
1104 In that case, invalid characters will be converted to underscores.
1105 If Name is $HOST, but no such environment variable exist,
1106 the hostname will be read using the gethostname() system call.
1108 @cindex PingInterval
1109 @item PingInterval = <@var{seconds}> (60)
1110 The number of seconds of inactivity that tinc will wait before sending a
1111 probe to the other end.
1114 @item PingTimeout = <@var{seconds}> (5)
1115 The number of seconds to wait for a response to pings or to allow meta
1116 connections to block. If the other end doesn't respond within this time,
1117 the connection is terminated, and the others will be notified of this.
1119 @cindex PriorityInheritance
1120 @item PriorityInheritance = <yes|no> (no) [experimental]
1121 When this option is enabled the value of the TOS field of tunneled IPv4 packets
1122 will be inherited by the UDP packets that are sent out.
1125 @item PrivateKey = <@var{key}> [obsolete]
1126 This is the RSA private key for tinc. However, for safety reasons it is
1127 advised to store private keys of any kind in separate files. This prevents
1128 accidental eavesdropping if you are editting the configuration file.
1130 @cindex PrivateKeyFile
1131 @item PrivateKeyFile = <@var{path}> (@file{@value{sysconfdir}/tinc/@var{netname}/rsa_key.priv})
1132 This is the full path name of the RSA private key file that was
1133 generated by @samp{tincctl generate-keys}. It must be a full path, not a
1136 @cindex ProcessPriority
1137 @item ProcessPriority = <low|normal|high>
1138 When this option is used the priority of the tincd process will be adjusted.
1139 Increasing the priority may help to reduce latency and packet loss on the VPN.
1142 @item Proxy = socks4 | socks4 | http | exec @var{...} [experimental]
1143 Use a proxy when making outgoing connections.
1144 The following proxy types are currently supported:
1148 @item socks4 <@var{address}> <@var{port}> [<@var{username}>]
1149 Connects to the proxy using the SOCKS version 4 protocol.
1150 Optionally, a @var{username} can be supplied which will be passed on to the proxy server.
1153 @item socks4 <@var{address}> <@var{port}> [<@var{username}> <@var{password}>]
1154 Connect to the proxy using the SOCKS version 5 protocol.
1155 If a @var{username} and @var{password} are given, basic username/password authentication will be used,
1156 otherwise no authentication will be used.
1159 @item http <@var{address}> <@var{port}>
1160 Connects to the proxy and sends a HTTP CONNECT request.
1163 @item exec <@var{command}>
1164 Executes the given command which should set up the outgoing connection.
1165 The environment variables @env{NAME}, @env{NODE}, @env{REMOTEADDRES} and @env{REMOTEPORT} are available.
1168 @cindex ReplayWindow
1169 @item ReplayWindow = <bytes> (16)
1170 This is the size of the replay tracking window for each remote node, in bytes.
1171 The window is a bitfield which tracks 1 packet per bit, so for example
1172 the default setting of 16 will track up to 128 packets in the window. In high
1173 bandwidth scenarios, setting this to a higher value can reduce packet loss from
1174 the interaction of replay tracking with underlying real packet loss and/or
1175 reordering. Setting this to zero will disable replay tracking completely and
1176 pass all traffic, but leaves tinc vulnerable to replay-based attacks on your
1180 @cindex StrictSubnets
1181 @item StrictSubnets <yes|no> (no) [experimental]
1182 When this option is enabled tinc will only use Subnet statements which are
1183 present in the host config files in the local
1184 @file{@value{sysconfdir}/tinc/@var{netname}/hosts/} directory.
1186 @cindex TunnelServer
1187 @item TunnelServer = <yes|no> (no) [experimental]
1188 When this option is enabled tinc will no longer forward information between other tinc daemons,
1189 and will only allow connections with nodes for which host config files are present in the local
1190 @file{@value{sysconfdir}/tinc/@var{netname}/hosts/} directory.
1191 Setting this options also implicitly sets StrictSubnets.
1194 @item UDPRcvBuf = <bytes> (OS default)
1195 Sets the socket receive buffer size for the UDP socket, in bytes.
1196 If unset, the default buffer size will be used by the operating system.
1199 @item UDPSndBuf = <bytes> Pq OS default
1200 Sets the socket send buffer size for the UDP socket, in bytes.
1201 If unset, the default buffer size will be used by the operating system.
1206 @c ==================================================================
1207 @node Host configuration variables
1208 @subsection Host configuration variables
1212 @item Address = <@var{IP address}|@var{hostname}> [<port>] [recommended]
1213 This variable is only required if you want to connect to this host. It
1214 must resolve to the external IP address where the host can be reached,
1215 not the one that is internal to the VPN.
1216 If no port is specified, the default Port is used.
1219 @item Cipher = <@var{cipher}> (blowfish)
1220 The symmetric cipher algorithm used to encrypt UDP packets.
1221 Any cipher supported by OpenSSL is recognized.
1222 Furthermore, specifying "none" will turn off packet encryption.
1223 It is best to use only those ciphers which support CBC mode.
1226 @item ClampMSS = <yes|no> (yes)
1227 This option specifies whether tinc should clamp the maximum segment size (MSS)
1228 of TCP packets to the path MTU. This helps in situations where ICMP
1229 Fragmentation Needed or Packet too Big messages are dropped by firewalls.
1232 @item Compression = <@var{level}> (0)
1233 This option sets the level of compression used for UDP packets.
1234 Possible values are 0 (off), 1 (fast zlib) and any integer up to 9 (best zlib),
1235 10 (fast lzo) and 11 (best lzo).
1238 @item Digest = <@var{digest}> (sha1)
1239 The digest algorithm used to authenticate UDP packets.
1240 Any digest supported by OpenSSL is recognized.
1241 Furthermore, specifying "none" will turn off packet authentication.
1243 @cindex IndirectData
1244 @item IndirectData = <yes|no> (no)
1245 When set to yes, other nodes which do not already have a meta connection to you
1246 will not try to establish direct communication with you.
1247 It is best to leave this option out or set it to no.
1250 @item MACLength = <@var{bytes}> (4)
1251 The length of the message authentication code used to authenticate UDP packets.
1252 Can be anything from 0
1253 up to the length of the digest produced by the digest algorithm.
1256 @item PMTU = <@var{mtu}> (1514)
1257 This option controls the initial path MTU to this node.
1259 @cindex PMTUDiscovery
1260 @item PMTUDiscovery = <yes|no> (yes)
1261 When this option is enabled, tinc will try to discover the path MTU to this node.
1262 After the path MTU has been discovered, it will be enforced on the VPN.
1265 @item Port = <@var{port}> (655)
1266 This is the port this tinc daemon listens on.
1267 You can use decimal portnumbers or symbolic names (as listed in @file{/etc/services}).
1270 @item PublicKey = <@var{key}> [obsolete]
1271 This is the RSA public key for this host.
1273 @cindex PublicKeyFile
1274 @item PublicKeyFile = <@var{path}> [obsolete]
1275 This is the full path name of the RSA public key file that was generated
1276 by @samp{tincctl generate-keys}. It must be a full path, not a relative
1280 From version 1.0pre4 on tinc will store the public key directly into the
1281 host configuration file in PEM format, the above two options then are not
1282 necessary. Either the PEM format is used, or exactly
1283 @strong{one of the above two options} must be specified
1284 in each host configuration file, if you want to be able to establish a
1285 connection with that host.
1288 @item Subnet = <@var{address}[/@var{prefixlength}[#@var{weight}]]>
1289 The subnet which this tinc daemon will serve.
1290 Tinc tries to look up which other daemon it should send a packet to by searching the appropiate subnet.
1291 If the packet matches a subnet,
1292 it will be sent to the daemon who has this subnet in his host configuration file.
1293 Multiple subnet lines can be specified for each daemon.
1295 Subnets can either be single MAC, IPv4 or IPv6 addresses,
1296 in which case a subnet consisting of only that single address is assumed,
1297 or they can be a IPv4 or IPv6 network address with a prefixlength.
1298 For example, IPv4 subnets must be in a form like 192.168.1.0/24,
1299 where 192.168.1.0 is the network address and 24 is the number of bits set in the netmask.
1300 Note that subnets like 192.168.1.1/24 are invalid!
1301 Read a networking HOWTO/FAQ/guide if you don't understand this.
1302 IPv6 subnets are notated like fec0:0:0:1::/64.
1303 MAC addresses are notated like 0:1a:2b:3c:4d:5e.
1305 @cindex CIDR notation
1306 Prefixlength is the number of bits set to 1 in the netmask part; for
1307 example: netmask 255.255.255.0 would become /24, 255.255.252.0 becomes
1308 /22. This conforms to standard CIDR notation as described in
1309 @uref{http://www.ietf.org/rfc/rfc1519.txt, RFC1519}
1311 A Subnet can be given a weight to indicate its priority over identical Subnets
1312 owned by different nodes. The default weight is 10. Lower values indicate
1313 higher priority. Packets will be sent to the node with the highest priority,
1314 unless that node is not reachable, in which case the node with the next highest
1315 priority will be tried, and so on.
1318 @item TCPonly = <yes|no> (no)
1319 If this variable is set to yes, then the packets are tunnelled over a
1320 TCP connection instead of a UDP connection. This is especially useful
1321 for those who want to run a tinc daemon from behind a masquerading
1322 firewall, or if UDP packet routing is disabled somehow.
1323 Setting this options also implicitly sets IndirectData.
1327 @c ==================================================================
1332 Apart from reading the server and host configuration files,
1333 tinc can also run scripts at certain moments.
1334 Under Windows (not Cygwin), the scripts should have the extension .bat.
1338 @item @value{sysconfdir}/tinc/@var{netname}/tinc-up
1339 This is the most important script.
1340 If it is present it will be executed right after the tinc daemon has been
1341 started and has connected to the virtual network device.
1342 It should be used to set up the corresponding network interface,
1343 but can also be used to start other things.
1344 Under Windows you can use the Network Connections control panel instead of creating this script.
1347 @item @value{sysconfdir}/tinc/@var{netname}/tinc-down
1348 This script is started right before the tinc daemon quits.
1350 @item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-up
1351 This script is started when the tinc daemon with name @var{host} becomes reachable.
1353 @item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-down
1354 This script is started when the tinc daemon with name @var{host} becomes unreachable.
1356 @item @value{sysconfdir}/tinc/@var{netname}/host-up
1357 This script is started when any host becomes reachable.
1359 @item @value{sysconfdir}/tinc/@var{netname}/host-down
1360 This script is started when any host becomes unreachable.
1362 @item @value{sysconfdir}/tinc/@var{netname}/subnet-up
1363 This script is started when a Subnet becomes reachable.
1364 The Subnet and the node it belongs to are passed in environment variables.
1366 @item @value{sysconfdir}/tinc/@var{netname}/subnet-down
1367 This script is started when a Subnet becomes unreachable.
1370 @cindex environment variables
1371 The scripts are started without command line arguments,
1372 but can make use of certain environment variables.
1373 Under UNIX like operating systems the names of environment variables must be preceded by a $ in scripts.
1374 Under Windows, in @file{.bat} files, they have to be put between % signs.
1379 If a netname was specified, this environment variable contains it.
1383 Contains the name of this tinc daemon.
1387 Contains the name of the virtual network device that tinc uses.
1391 Contains the name of the virtual network interface that tinc uses.
1392 This should be used for commands like ifconfig.
1396 When a host becomes (un)reachable, this is set to its name.
1397 If a subnet becomes (un)reachable, this is set to the owner of that subnet.
1399 @cindex REMOTEADDRESS
1401 When a host becomes (un)reachable, this is set to its real address.
1405 When a host becomes (un)reachable,
1406 this is set to the port number it uses for communication with other tinc daemons.
1410 When a subnet becomes (un)reachable, this is set to the subnet.
1415 @c ==================================================================
1416 @node How to configure
1417 @subsection How to configure
1419 @subsubheading Step 1. Creating initial configuration files.
1421 The initial directory structure, configuration files and public/private keypairs are created using the following command:
1424 tincctl -n @var{netname} init @var{name}
1427 (You will need to run this as root, or use "sudo".)
1428 This will create the configuration directory @file{@value{sysconfdir}/tinc/@var{netname}.},
1429 and inside it will create another directory named @file{hosts/}.
1430 In the configuration directory, it will create the file @file{tinc.conf} with the following contents:
1436 It will also create private RSA and ECDSA keys, which will be stored in the files @file{rsa_key.priv} and @file{ecdsa_key.priv}.
1437 It will also create a host configuration file @file{hosts/@var{name}},
1438 which will contain the corresponding public RSA and ECDSA keys.
1440 Finally, on UNIX operating systems, it will create an executable script @file{tinc-up},
1441 which will initially not do anything except warning that you should edit it.
1443 @subsubheading Step 2. Modifying the initial configuration.
1445 Unless you want to use tinc in switch mode,
1446 you should now configure which range of addresses you will use on the VPN.
1447 Let's assume you will be part of a VPN which uses the address range 192.168.0.0/16,
1448 and you yourself have a smaller portion of that range: 192.168.2.0/24.
1449 Then you should run the following command:
1452 tincctl -n @var{netname} config add subnet 192.168.2.0/24
1455 This will add a Subnet statement to your host configuration file.
1456 Try opening the file @file{@value{sysconfdir}/tinc/@var{netname}/hosts/@var{name}} in an editor.
1457 You should now see a file containing the public RSA and ECDSA keys (which looks like a bunch of random characters),
1458 and the following line at the bottom:
1461 Subnet = 192.168.2.0/24
1464 If you will use more than one address range, you can add more Subnets.
1465 For example, if you also use the IPv6 subnet fec0:0:0:2::/64, you can add it as well:
1468 tincctl -n @var{netname} config add subnet fec0:0:0:2::/24
1471 This will add another line to the file @file{hosts/@var{name}}.
1472 If you make a mistake, you can undo it by simply using @samp{config del} instead of @samp{config add}.
1474 If you want other tinc daemons to create meta-connections to your daemon,
1475 you should add your public IP address or hostname to your host configuration file.
1476 For example, if your hostname is foo.example.org, run:
1479 tincctl -n @var{netname} config add address foo.example.org
1482 If you already know to which daemons your daemon should make meta-connections,
1483 you should configure that now as well.
1484 Suppose you want to connect to a daemon named "bar", run:
1487 tincctl -n @var{netname} config add connectto bar
1490 Note that you specify the Name of the other daemon here, not an IP address or hostname!
1491 When you start tinc, and it tries to make a connection to "bar",
1492 it will look for a host configuration file named @file{hosts/bar},
1493 and will read Address statements and public keys from that file.
1495 @subsubheading Step 2. Exchanging configuration files.
1497 If your daemon has a ConnectTo = bar statement in its @file{tinc.conf} file,
1498 or if bar has a ConnectTo your daemon, then you both need each other's host configuration files.
1499 You should send @file{hosts/@var{name}} to bar, and bar should send you his file which you should move to @file{hosts/bar}.
1500 If you are on a UNIX platform, you can easily send an email containing the necessary information using the following command
1501 (assuming the owner of bar has the email address bar@@example.org):
1504 tincctl -n @var{netname} export | mail -s "My config file" bar@@example.org
1507 If the owner of bar does the same to send his host configuration file to you,
1508 you can probably pipe his email through the following command,
1509 or you can just start this command in a terminal and copy&paste the email:
1512 tincctl -n @var{netname} import
1515 If you are the owner of bar yourself, and you have SSH access to that computer,
1516 you can also swap the host configuration files using the following command:
1519 tincctl -n @var{netname} export \
1520 | ssh bar.example.org tincctl -n @var{netname} exchange \
1521 | tincctl -n @var{netname} import
1524 You should repeat this for all nodes you ConnectTo, or which ConnectTo you.
1525 However, remember that you do not need to ConnectTo all nodes in the VPN;
1526 it is only necessary to create one or a few meta-connections,
1527 after the connections are made tinc will learn about all the other nodes in the VPN,
1528 and will automatically make other connections as necessary.
1531 @c ==================================================================
1532 @node Network interfaces
1533 @section Network interfaces
1535 Before tinc can start transmitting data over the tunnel, it must
1536 set up the virtual network interface.
1538 First, decide which IP addresses you want to have associated with these
1539 devices, and what network mask they must have.
1541 Tinc will open a virtual network device (@file{/dev/tun}, @file{/dev/tap0} or similar),
1542 which will also create a network interface called something like @samp{tun0}, @samp{tap0}.
1543 If you are using the Linux tun/tap driver, the network interface will by default have the same name as the @var{netname}.
1544 Under Windows you can change the name of the network interface from the Network Connections control panel.
1547 You can configure the network interface by putting ordinary ifconfig, route, and other commands
1548 to a script named @file{@value{sysconfdir}/tinc/@var{netname}/tinc-up}.
1549 When tinc starts, this script will be executed. When tinc exits, it will execute the script named
1550 @file{@value{sysconfdir}/tinc/@var{netname}/tinc-down}, but normally you don't need to create that script.
1551 You can manually open the script in an editor, or use the following command:
1554 tincctl -n @var{netname} edit tinc-up
1557 An example @file{tinc-up} script, that would be appropriate for the scenario in the previous section, is:
1561 ifconfig $INTERFACE 192.168.2.1 netmask 255.255.0.0
1562 ip addr add fec0:0:0:2::/48 dev $INTERFACE
1565 The first command gives the interface an IPv4 address and a netmask.
1566 The kernel will also automatically add an IPv4 route to this interface, so normally you don't need
1567 to add route commands to the @file{tinc-up} script.
1568 The kernel will also bring the interface up after this command.
1570 The netmask is the mask of the @emph{entire} VPN network, not just your
1572 The second command gives the interface an IPv6 address and netmask,
1573 which will also automatically add an IPv6 route.
1574 If you only want to use "ip addr" commands on Linux, don't forget that it doesn't bring the interface up, unlike ifconfig,
1575 so you need to add @samp{ip link set $INTERFACE up} in that case.
1577 The exact syntax of the ifconfig and route commands differs from platform to platform.
1578 You can look up the commands for setting addresses and adding routes in @ref{Platform specific information},
1579 but it is best to consult the manpages of those utilities on your platform.
1582 @c ==================================================================
1583 @node Example configuration
1584 @section Example configuration
1588 Imagine the following situation. Branch A of our example `company' wants to connect
1589 three branch offices in B, C and D using the Internet. All four offices
1590 have a 24/7 connection to the Internet.
1592 A is going to serve as the center of the network. B and C will connect
1593 to A, and D will connect to C. Each office will be assigned their own IP
1597 A: net 10.1.0.0 mask 255.255.0.0 gateway 10.1.54.1 internet IP 1.2.3.4
1598 B: net 10.2.0.0 mask 255.255.0.0 gateway 10.2.1.12 internet IP 2.3.4.5
1599 C: net 10.3.0.0 mask 255.255.0.0 gateway 10.3.69.254 internet IP 3.4.5.6
1600 D: net 10.4.0.0 mask 255.255.0.0 gateway 10.4.3.32 internet IP 4.5.6.7
1603 Here, ``gateway'' is the VPN IP address of the machine that is running the
1604 tincd, and ``internet IP'' is the IP address of the firewall, which does not
1605 need to run tincd, but it must do a port forwarding of TCP and UDP on port
1606 655 (unless otherwise configured).
1608 In this example, it is assumed that eth0 is the interface that points to
1609 the inner (physical) LAN of the office, although this could also be the
1610 same as the interface that leads to the Internet. The configuration of
1611 the real interface is also shown as a comment, to give you an idea of
1612 how these example host is set up. All branches use the netname `company'
1613 for this particular VPN.
1615 Each branch is set up using the @samp{tincctl init} and @samp{tincctl config} commands,
1616 here we just show the end results:
1618 @subsubheading For Branch A
1620 @emph{BranchA} would be configured like this:
1622 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1627 # Real interface of internal network:
1628 # ifconfig eth0 10.1.54.1 netmask 255.255.0.0
1630 ifconfig $INTERFACE 10.1.54.1 netmask 255.0.0.0
1633 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1639 On all hosts, @file{@value{sysconfdir}/tinc/company/hosts/BranchA} contains:
1642 Subnet = 10.1.0.0/16
1645 -----BEGIN RSA PUBLIC KEY-----
1647 -----END RSA PUBLIC KEY-----
1650 Note that the IP addresses of eth0 and the VPN interface are the same.
1651 This is quite possible, if you make sure that the netmasks of the interfaces are different.
1652 It is in fact recommended to give both real internal network interfaces and VPN interfaces the same IP address,
1653 since that will make things a lot easier to remember and set up.
1656 @subsubheading For Branch B
1658 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1663 # Real interface of internal network:
1664 # ifconfig eth0 10.2.43.8 netmask 255.255.0.0
1666 ifconfig $INTERFACE 10.2.1.12 netmask 255.0.0.0
1669 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1676 Note here that the internal address (on eth0) doesn't have to be the
1677 same as on the VPN interface. Also, ConnectTo is given so that this node will
1678 always try to connect to BranchA.
1680 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchB}:
1683 Subnet = 10.2.0.0/16
1686 -----BEGIN RSA PUBLIC KEY-----
1688 -----END RSA PUBLIC KEY-----
1692 @subsubheading For Branch C
1694 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1699 # Real interface of internal network:
1700 # ifconfig eth0 10.3.69.254 netmask 255.255.0.0
1702 ifconfig $INTERFACE 10.3.69.254 netmask 255.0.0.0
1705 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1712 C already has another daemon that runs on port 655, so they have to
1713 reserve another port for tinc. It knows the portnumber it has to listen on
1714 from it's own host configuration file.
1716 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchC}:
1720 Subnet = 10.3.0.0/16
1723 -----BEGIN RSA PUBLIC KEY-----
1725 -----END RSA PUBLIC KEY-----
1729 @subsubheading For Branch D
1731 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1736 # Real interface of internal network:
1737 # ifconfig eth0 10.4.3.32 netmask 255.255.0.0
1739 ifconfig $INTERFACE 10.4.3.32 netmask 255.0.0.0
1742 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1749 D will be connecting to C, which has a tincd running for this network on
1750 port 2000. It knows the port number from the host configuration file.
1752 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchD}:
1755 Subnet = 10.4.0.0/16
1758 -----BEGIN RSA PUBLIC KEY-----
1760 -----END RSA PUBLIC KEY-----
1763 @subsubheading Key files
1765 A, B, C and D all have their own public/private keypairs:
1767 The private RSA key is stored in @file{@value{sysconfdir}/tinc/company/rsa_key.priv},
1768 the private ECDSA key is stored in @file{@value{sysconfdir}/tinc/company/ecdsa_key.priv},
1769 and the public RSA and ECDSA keys are put into the host configuration file in the @file{@value{sysconfdir}/tinc/company/hosts/} directory.
1771 @subsubheading Starting
1773 After each branch has finished configuration and they have distributed
1774 the host configuration files amongst them, they can start their tinc daemons.
1775 They don't necessarily have to wait for the other branches to have started
1776 their daemons, tinc will try connecting until they are available.
1779 @c ==================================================================
1781 @chapter Running tinc
1783 If everything else is done, you can start tinc by typing the following command:
1786 tincctl -n @var{netname} start
1790 Tinc will detach from the terminal and continue to run in the background like a good daemon.
1791 If there are any problems however you can try to increase the debug level
1792 and look in the syslog to find out what the problems are.
1798 * Solving problems::
1800 * Sending bug reports::
1804 @c ==================================================================
1805 @node Runtime options
1806 @section Runtime options
1808 Besides the settings in the configuration file, tinc also accepts some
1809 command line options.
1811 @cindex command line
1812 @cindex runtime options
1816 @item -c, --config=@var{path}
1817 Read configuration options from the directory @var{path}. The default is
1818 @file{@value{sysconfdir}/tinc/@var{netname}/}.
1820 @item -D, --no-detach
1821 Don't fork and detach.
1822 This will also disable the automatic restart mechanism for fatal errors.
1825 @item -d, --debug=@var{level}
1826 Set debug level to @var{level}. The higher the debug level, the more gets
1827 logged. Everything goes via syslog.
1829 @item -n, --net=@var{netname}
1830 Use configuration for net @var{netname}.
1831 This will let tinc read all configuration files from
1832 @file{@value{sysconfdir}/tinc/@var{netname}/}.
1833 Specifying . for @var{netname} is the same as not specifying any @var{netname}.
1834 @xref{Multiple networks}.
1836 @item --pidfile=@var{filename}
1837 Store a cookie in @var{filename} which allows tincctl to authenticate.
1838 If unspecified, the default is
1839 @file{@value{localstatedir}/run/tinc.@var{netname}.pid}.
1841 @item -o, --option=[@var{HOST}.]@var{KEY}=@var{VALUE}
1842 Without specifying a @var{HOST}, this will set server configuration variable @var{KEY} to @var{VALUE}.
1843 If specified as @var{HOST}.@var{KEY}=@var{VALUE},
1844 this will set the host configuration variable @var{KEY} of the host named @var{HOST} to @var{VALUE}.
1845 This option can be used more than once to specify multiple configuration variables.
1848 Lock tinc into main memory.
1849 This will prevent sensitive data like shared private keys to be written to the system swap files/partitions.
1851 This option is not supported on all platforms.
1853 @item --logfile[=@var{file}]
1854 Write log entries to a file instead of to the system logging facility.
1855 If @var{file} is omitted, the default is @file{@value{localstatedir}/log/tinc.@var{netname}.log}.
1857 @item --bypass-security
1858 Disables encryption and authentication.
1859 Only useful for debugging.
1862 Change process root directory to the directory where the config file is
1863 located (@file{@value{sysconfdir}/tinc/@var{netname}/} as determined by
1864 -n/--net option or as given by -c/--config option), for added security.
1865 The chroot is performed after all the initialization is done, after
1866 writing pid files and opening network sockets.
1868 Note that this option alone does not do any good without -U/--user, below.
1870 Note also that tinc can't run scripts anymore (such as tinc-down or host-up),
1871 unless it's setup to be runnable inside chroot environment.
1873 This option is not supported on all platforms.
1874 @item -U, --user=@var{user}
1875 Switch to the given @var{user} after initialization, at the same time as
1876 chroot is performed (see --chroot above). With this option tinc drops
1877 privileges, for added security.
1879 This option is not supported on all platforms.
1882 Display a short reminder of these runtime options and terminate.
1885 Output version information and exit.
1889 @c ==================================================================
1894 You can also send the following signals to a running tincd process:
1900 Forces tinc to try to connect to all uplinks immediately.
1901 Usually tinc attempts to do this itself,
1902 but increases the time it waits between the attempts each time it failed,
1903 and if tinc didn't succeed to connect to an uplink the first time after it started,
1904 it defaults to the maximum time of 15 minutes.
1907 Partially rereads configuration files.
1908 Connections to hosts whose host config file are removed are closed.
1909 New outgoing connections specified in @file{tinc.conf} will be made.
1910 If the --logfile option is used, this will also close and reopen the log file,
1911 useful when log rotation is used.
1915 @c ==================================================================
1917 @section Debug levels
1919 @cindex debug levels
1920 The tinc daemon can send a lot of messages to the syslog.
1921 The higher the debug level, the more messages it will log.
1922 Each level inherits all messages of the previous level:
1928 This will log a message indicating tinc has started along with a version number.
1929 It will also log any serious error.
1932 This will log all connections that are made with other tinc daemons.
1935 This will log status and error messages from scripts and other tinc daemons.
1938 This will log all requests that are exchanged with other tinc daemons. These include
1939 authentication, key exchange and connection list updates.
1942 This will log a copy of everything received on the meta socket.
1945 This will log all network traffic over the virtual private network.
1949 @c ==================================================================
1950 @node Solving problems
1951 @section Solving problems
1953 If tinc starts without problems, but if the VPN doesn't work, you will have to find the cause of the problem.
1954 The first thing to do is to start tinc with a high debug level in the foreground,
1955 so you can directly see everything tinc logs:
1958 tincd -n @var{netname} -d5 -D
1961 If tinc does not log any error messages, then you might want to check the following things:
1964 @item @file{tinc-up} script
1965 Does this script contain the right commands?
1966 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.
1969 Does the Subnet (or Subnets) in the host configuration file of this host match the portion of the VPN that belongs to this host?
1971 @item Firewalls and NATs
1972 Do you have a firewall or a NAT device (a masquerading firewall or perhaps an ADSL router that performs masquerading)?
1973 If so, check that it allows TCP and UDP traffic on port 655.
1974 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.
1975 You can add @samp{TCPOnly = yes} to your host config file to force tinc to only use a single TCP connection,
1976 this works through most firewalls and NATs.
1981 @c ==================================================================
1982 @node Error messages
1983 @section Error messages
1985 What follows is a list of the most common error messages you might find in the logs.
1986 Some of them will only be visible if the debug level is high enough.
1989 @item Could not open /dev/tap0: No such device
1992 @item You forgot to `modprobe netlink_dev' or `modprobe ethertap'.
1993 @item You forgot to compile `Netlink device emulation' in the kernel.
1996 @item Can't write to /dev/net/tun: No such device
1999 @item You forgot to `modprobe tun'.
2000 @item You forgot to compile `Universal TUN/TAP driver' in the kernel.
2001 @item The tun device is located somewhere else in @file{/dev/}.
2004 @item Network address and prefix length do not match!
2007 @item The Subnet field must contain a @emph{network} address, trailing bits should be 0.
2008 @item If you only want to use one IP address, set the netmask to /32.
2011 @item Error reading RSA key file `rsa_key.priv': No such file or directory
2014 @item You forgot to create a public/private keypair.
2015 @item Specify the complete pathname to the private key file with the @samp{PrivateKeyFile} option.
2018 @item Warning: insecure file permissions for RSA private key file `rsa_key.priv'!
2021 @item The private key file is readable by users other than root.
2022 Use chmod to correct the file permissions.
2025 @item Creating metasocket failed: Address family not supported
2028 @item By default tinc tries to create both IPv4 and IPv6 sockets.
2029 On some platforms this might not be implemented.
2030 If the logs show @samp{Ready} later on, then at least one metasocket was created,
2031 and you can ignore this message.
2032 You can add @samp{AddressFamily = ipv4} to @file{tinc.conf} to prevent this from happening.
2035 @item Cannot route packet: unknown IPv4 destination 1.2.3.4
2038 @item You try to send traffic to a host on the VPN for which no Subnet is known.
2039 @item If it is a broadcast address (ending in .255), it probably is a samba server or a Windows host sending broadcast packets.
2043 @item Cannot route packet: ARP request for unknown address 1.2.3.4
2046 @item You try to send traffic to a host on the VPN for which no Subnet is known.
2049 @item Packet with destination 1.2.3.4 is looping back to us!
2052 @item Something is not configured right. Packets are being sent out to the
2053 virtual network device, but according to the Subnet directives in your host configuration
2054 file, those packets should go to your own host. Most common mistake is that
2055 you have a Subnet line in your host configuration file with a prefix length which is
2056 just as large as the prefix of the virtual network interface. The latter should in almost all
2057 cases be larger. Rethink your configuration.
2058 Note that you will only see this message if you specified a debug
2059 level of 5 or higher!
2060 @item Chances are that a @samp{Subnet = ...} line in the host configuration file of this tinc daemon is wrong.
2061 Change it to a subnet that is accepted locally by another interface,
2062 or if that is not the case, try changing the prefix length into /32.
2065 @item Node foo (1.2.3.4) is not reachable
2068 @item Node foo does not have a connection anymore, its tinc daemon is not running or its connection to the Internet is broken.
2071 @item Received UDP packet from unknown source 1.2.3.4 (port 12345)
2074 @item If you see this only sporadically, it is harmless and caused by a node sending packets using an old key.
2075 @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.
2076 You can add @samp{TCPOnly = yes} to host configuration files to force all VPN traffic to go over a TCP connection.
2079 @item Got bad/bogus/unauthorized REQUEST from foo (1.2.3.4 port 12345)
2082 @item Node foo does not have the right public/private keypair.
2083 Generate new keypairs and distribute them again.
2084 @item An attacker tries to gain access to your VPN.
2085 @item A network error caused corruption of metadata sent from foo.
2090 @c ==================================================================
2091 @node Sending bug reports
2092 @section Sending bug reports
2094 If you really can't find the cause of a problem, or if you suspect tinc is not working right,
2095 you can send us a bugreport, see @ref{Contact information}.
2096 Be sure to include the following information in your bugreport:
2099 @item A clear description of what you are trying to achieve and what the problem is.
2100 @item What platform (operating system, version, hardware architecture) and which version of tinc you use.
2101 @item If compiling tinc fails, a copy of @file{config.log} and the error messages you get.
2102 @item Otherwise, a copy of @file{tinc.conf}, @file{tinc-up} and all files in the @file{hosts/} directory.
2103 @item The output of the commands @samp{ifconfig -a} and @samp{route -n} (or @samp{netstat -rn} if that doesn't work).
2104 @item The output of any command that fails to work as it should (like ping or traceroute).
2107 @c ==================================================================
2108 @node Controlling tinc
2109 @chapter Controlling tinc
2111 You can control and inspect a running tincd through the tincctl
2112 command. A quick example:
2115 tincctl -n @var{netname} reload
2119 * tincctl runtime options::
2120 * tincctl environment variables::
2121 * tincctl commands::
2122 * tincctl examples::
2127 @c ==================================================================
2128 @node tincctl runtime options
2129 @section tincctl runtime options
2133 @item -c, --config=@var{path}
2134 Read configuration options from the directory @var{path}. The default is
2135 @file{@value{sysconfdir}/tinc/@var{netname}/}.
2137 @item -n, --net=@var{netname}
2138 Use configuration for net @var{netname}. @xref{Multiple networks}.
2140 @item --pidfile=@var{filename}
2141 Use the cookie from @var{filename} to authenticate with a running tinc daemon.
2142 If unspecified, the default is
2143 @file{@value{localstatedir}/run/tinc.@var{netname}.pid}.
2146 Display a short reminder of runtime options and commands, then terminate.
2149 Output version information and exit.
2153 @c ==================================================================
2154 @node tincctl environment variables
2155 @section tincctl environment variables
2160 If no netname is specified on the command line with the @option{-n} option,
2161 the value of this environment variable is used.
2164 @c ==================================================================
2165 @node tincctl commands
2166 @section tincctl commands
2171 @item init [@var{name}]
2172 Create initial configuration files and RSA and ECDSA keypairs with default length.
2173 If no @var{name} for this node is given, it will be asked for.
2175 @item config [get] @var{variable}
2176 Print the current value of configuration variable @var{variable}.
2177 If more than one variable with the same name exists,
2178 the value of each of them will be printed on a separate line.
2180 @item config [set] @var{variable} @var{value}
2181 Set configuration variable @var{variable} to the given @var{value}.
2182 All previously existing configuration variables with the same name are removed.
2183 To set a variable for a specific host, use the notation @var{host}.@var{variable}.
2185 @item config add @var{variable} @var{value}
2186 As above, but without removing any previously existing configuration variables.
2188 @item config del @var{variable} [@var{value}]
2189 Remove configuration variables with the same name and @var{value}.
2190 If no @var{value} is given, all configuration variables with the same name will be removed.
2192 @item edit @var{filename}
2193 Start an editor for the given configuration file.
2194 You do not need to specify the full path to the file.
2197 Export the host configuration file of the local node to standard output.
2200 Export all host configuration files to standard output.
2202 @item import [--force]
2203 Import host configuration file(s) generated by the tincctl export command from standard input.
2204 Already existing host configuration files are not overwritten unless the option --force is used.
2206 @item exchange [--force]
2207 The same as export followed by import.
2209 @item exchange-all [--force]
2210 The same as export-all followed by import.
2212 @item start [tincd options]
2213 Start @samp{tincd}, optionally with the given extra options.
2219 Restart @samp{tincd}.
2222 Partially rereads configuration files. Connections to hosts whose host
2223 config files are removed are closed. New outgoing connections specified
2224 in @file{tinc.conf} will be made.
2227 Shows the PID of the currently running @samp{tincd}.
2229 @item generate-keys [@var{bits}]
2230 Generate public/private keypair of @var{bits} length. If @var{bits} is not specified,
2231 1024 is the default. tinc will ask where you want to store the files,
2232 but will default to the configuration directory (you can use the -c or -n
2235 @item dump [reachable] nodes
2236 Dump a list of all known nodes in the VPN.
2237 If the reachable keyword is used, only lists reachable nodes.
2240 Dump a list of all known connections in the VPN.
2243 Dump a list of all known subnets in the VPN.
2245 @item dump connections
2246 Dump a list of all meta connections with ourself.
2248 @item dump graph | digraph
2249 Dump a graph of the VPN in dotty format.
2250 Nodes are colored according to their reachability:
2251 red nodes are unreachable, orange nodes are indirectly reachable, green nodes are directly reachable.
2252 Black nodes are either directly or indirectly reachable, but direct reachability has not been tried yet.
2254 @item info @var{node} | @var{subnet} | @var{address}
2255 Show information about a particular @var{node}, @var{subnet} or @var{address}.
2256 If an @var{address} is given, any matching subnet will be shown.
2259 Purges all information remembered about unreachable nodes.
2261 @item debug @var{level}
2262 Sets debug level to @var{level}.
2264 @item log [@var{level}]
2265 Capture log messages from a running tinc daemon.
2266 An optional debug level can be given that will be applied only for log messages sent to tincctl.
2269 Forces tinc to try to connect to all uplinks immediately.
2270 Usually tinc attempts to do this itself,
2271 but increases the time it waits between the attempts each time it failed,
2272 and if tinc didn't succeed to connect to an uplink the first time after it started,
2273 it defaults to the maximum time of 15 minutes.
2275 @item disconnect @var{node}
2276 Closes the meta connection with the given @var{node}.
2279 If tincctl is compiled with libcurses support, this will display live traffic statistics for all the known nodes,
2280 similar to the UNIX top command.
2281 See below for more information.
2284 Dump VPN traffic going through the local tinc node in pcap-savefile format to standard output,
2285 from where it can be redirected to a file or piped through a program that can parse it directly,
2290 @c ==================================================================
2291 @node tincctl examples
2292 @section tincctl examples
2294 Examples of some commands:
2297 tincctl -n vpn dump graph | circo -Txlib
2298 tincctl -n vpn pcap | tcpdump -r -
2302 Example of configuring tinc using tincctl:
2305 tincctl -n vpn init foo
2306 tincctl -n vpn config Subnet 192.168.1.0/24
2307 tincctl -n vpn config bar.Address bar.example.com
2308 tincctl -n vpn config ConnectTo bar
2309 tincctl -n vpn export | gpg --clearsign | mail -s "My config" vpnmaster@@example.com
2312 @c ==================================================================
2314 @section tincctl top
2316 The top command connects to a running tinc daemon and repeatedly queries its per-node traffic counters.
2317 It displays a list of all the known nodes in the left-most column,
2318 and the amount of bytes and packets read from and sent to each node in the other columns.
2319 By default, the information is updated every second.
2320 The behaviour of the top command can be changed using the following keys:
2325 Change the interval between updates.
2326 After pressing the @key{s} key, enter the desired interval in seconds, followed by enter.
2327 Fractional seconds are honored.
2328 Intervals lower than 0.1 seconds are not allowed.
2331 Toggle between displaying current traffic rates (in packets and bytes per second)
2332 and cummulative traffic (total packets and bytes since the tinc daemon started).
2335 Sort the list of nodes by name.
2338 Sort the list of nodes by incoming amount of bytes.
2341 Sort the list of nodes by incoming amount of packets.
2344 Sort the list of nodes by outgoing amount of bytes.
2347 Sort the list of nodes by outgoing amount of packets.
2350 Sort the list of nodes by sum of incoming and outgoing amount of bytes.
2353 Sort the list of nodes by sum of incoming and outgoing amount of packets.
2356 Show amount of traffic in bytes.
2359 Show amount of traffic in kilobytes.
2362 Show amount of traffic in megabytes.
2365 Show amount of traffic in gigabytes.
2373 @c ==================================================================
2374 @node Technical information
2375 @chapter Technical information
2380 * The meta-protocol::
2385 @c ==================================================================
2386 @node The connection
2387 @section The connection
2390 Tinc is a daemon that takes VPN data and transmit that to another host
2391 computer over the existing Internet infrastructure.
2395 * The meta-connection::
2399 @c ==================================================================
2400 @node The UDP tunnel
2401 @subsection The UDP tunnel
2403 @cindex virtual network device
2405 The data itself is read from a character device file, the so-called
2406 @emph{virtual network device}. This device is associated with a network
2407 interface. Any data sent to this interface can be read from the device,
2408 and any data written to the device gets sent from the interface.
2409 There are two possible types of virtual network devices:
2410 `tun' style, which are point-to-point devices which can only handle IPv4 and/or IPv6 packets,
2411 and `tap' style, which are Ethernet devices and handle complete Ethernet frames.
2413 So when tinc reads an Ethernet frame from the device, it determines its
2414 type. When tinc is in it's default routing mode, it can handle IPv4 and IPv6
2415 packets. Depending on the Subnet lines, it will send the packets off to their destination IP address.
2416 In the `switch' and `hub' mode, tinc will use broadcasts and MAC address discovery
2417 to deduce the destination of the packets.
2418 Since the latter modes only depend on the link layer information,
2419 any protocol that runs over Ethernet is supported (for instance IPX and Appletalk).
2420 However, only `tap' style devices provide this information.
2422 After the destination has been determined,
2423 the packet will be compressed (optionally),
2424 a sequence number will be added to the packet,
2425 the packet will then be encrypted
2426 and a message authentication code will be appended.
2428 @cindex encapsulating
2430 When that is done, time has come to actually transport the
2431 packet to the destination computer. We do this by sending the packet
2432 over an UDP connection to the destination host. This is called
2433 @emph{encapsulating}, the VPN packet (though now encrypted) is
2434 encapsulated in another IP datagram.
2436 When the destination receives this packet, the same thing happens, only
2437 in reverse. So it checks the message authentication code, decrypts the contents of the UDP datagram,
2438 checks the sequence number
2439 and writes the decrypted information to its own virtual network device.
2441 If the virtual network device is a `tun' device (a point-to-point tunnel),
2442 there is no problem for the kernel to accept a packet.
2443 However, if it is a `tap' device (this is the only available type on FreeBSD),
2444 the destination MAC address must match that of the virtual network interface.
2445 If tinc is in it's default routing mode, ARP does not work, so the correct destination MAC
2446 can not be known by the sending host.
2447 Tinc solves this by letting the receiving end detect the MAC address of its own virtual network interface
2448 and overwriting the destination MAC address of the received packet.
2450 In switch or hub modes ARP does work so the sender already knows the correct destination MAC address.
2451 In those modes every interface should have a unique MAC address, so make sure they are not the same.
2452 Because switch and hub modes rely on MAC addresses to function correctly,
2453 these modes cannot be used on the following operating systems which don't have a `tap' style virtual network device:
2454 OpenBSD, NetBSD, Darwin and Solaris.
2457 @c ==================================================================
2458 @node The meta-connection
2459 @subsection The meta-connection
2461 Having only a UDP connection available is not enough. Though suitable
2462 for transmitting data, we want to be able to reliably send other
2463 information, such as routing and session key information to somebody.
2466 TCP is a better alternative, because it already contains protection
2467 against information being lost, unlike UDP.
2469 So we establish two connections. One for the encrypted VPN data, and one
2470 for other information, the meta-data. Hence, we call the second
2471 connection the meta-connection. We can now be sure that the
2472 meta-information doesn't get lost on the way to another computer.
2474 @cindex data-protocol
2475 @cindex meta-protocol
2476 Like with any communication, we must have a protocol, so that everybody
2477 knows what everything stands for, and how she should react. Because we
2478 have two connections, we also have two protocols. The protocol used for
2479 the UDP data is the ``data-protocol,'' the other one is the
2482 The reason we don't use TCP for both protocols is that UDP is much
2483 better for encapsulation, even while it is less reliable. The real
2484 problem is that when TCP would be used to encapsulate a TCP stream
2485 that's on the private network, for every packet sent there would be
2486 three ACKs sent instead of just one. Furthermore, if there would be
2487 a timeout, both TCP streams would sense the timeout, and both would
2488 start re-sending packets.
2491 @c ==================================================================
2492 @node The meta-protocol
2493 @section The meta-protocol
2495 The meta protocol is used to tie all tinc daemons together, and
2496 exchange information about which tinc daemon serves which virtual
2499 The meta protocol consists of requests that can be sent to the other
2500 side. Each request has a unique number and several parameters. All
2501 requests are represented in the standard ASCII character set. It is
2502 possible to use tools such as telnet or netcat to connect to a tinc
2503 daemon started with the --bypass-security option
2504 and to read and write requests by hand, provided that one
2505 understands the numeric codes sent.
2507 The authentication scheme is described in @ref{Authentication protocol}. After a
2508 successful authentication, the server and the client will exchange all the
2509 information about other tinc daemons and subnets they know of, so that both
2510 sides (and all the other tinc daemons behind them) have their information
2517 ------------------------------------------------------------------
2518 ADD_EDGE node1 node2 21.32.43.54 655 222 0
2519 | | | | | +-> options
2520 | | | | +----> weight
2521 | | | +--------> UDP port of node2
2522 | | +----------------> real address of node2
2523 | +-------------------------> name of destination node
2524 +-------------------------------> name of source node
2526 ADD_SUBNET node 192.168.1.0/24
2527 | | +--> prefixlength
2528 | +--------> network address
2529 +------------------> owner of this subnet
2530 ------------------------------------------------------------------
2533 The ADD_EDGE messages are to inform other tinc daemons that a connection between
2534 two nodes exist. The address of the destination node is available so that
2535 VPN packets can be sent directly to that node.
2537 The ADD_SUBNET messages inform other tinc daemons that certain subnets belong
2538 to certain nodes. tinc will use it to determine to which node a VPN packet has
2545 ------------------------------------------------------------------
2546 DEL_EDGE node1 node2
2547 | +----> name of destination node
2548 +----------> name of source node
2550 DEL_SUBNET node 192.168.1.0/24
2551 | | +--> prefixlength
2552 | +--------> network address
2553 +------------------> owner of this subnet
2554 ------------------------------------------------------------------
2557 In case a connection between two daemons is closed or broken, DEL_EDGE messages
2558 are sent to inform the other daemons of that fact. Each daemon will calculate a
2559 new route to the the daemons, or mark them unreachable if there isn't any.
2566 ------------------------------------------------------------------
2567 REQ_KEY origin destination
2568 | +--> name of the tinc daemon it wants the key from
2569 +----------> name of the daemon that wants the key
2571 ANS_KEY origin destination 4ae0b0a82d6e0078 91 64 4
2572 | | \______________/ | | +--> MAC length
2573 | | | | +-----> digest algorithm
2574 | | | +--------> cipher algorithm
2575 | | +--> 128 bits key
2576 | +--> name of the daemon that wants the key
2577 +----------> name of the daemon that uses this key
2580 +--> daemon that has changed it's packet key
2581 ------------------------------------------------------------------
2584 The keys used to encrypt VPN packets are not sent out directly. This is
2585 because it would generate a lot of traffic on VPNs with many daemons, and
2586 chances are that not every tinc daemon will ever send a packet to every
2587 other daemon. Instead, if a daemon needs a key it sends a request for it
2588 via the meta connection of the nearest hop in the direction of the
2595 ------------------------------------------------------------------
2598 ------------------------------------------------------------------
2601 There is also a mechanism to check if hosts are still alive. Since network
2602 failures or a crash can cause a daemon to be killed without properly
2603 shutting down the TCP connection, this is necessary to keep an up to date
2604 connection list. PINGs are sent at regular intervals, except when there
2605 is also some other traffic. A little bit of salt (random data) is added
2606 with each PING and PONG message, to make sure that long sequences of PING/PONG
2607 messages without any other traffic won't result in known plaintext.
2609 This basically covers what is sent over the meta connection by tinc.
2612 @c ==================================================================
2618 Tinc got its name from ``TINC,'' short for @emph{There Is No Cabal}; the
2619 alleged Cabal was/is an organisation that was said to keep an eye on the
2620 entire Internet. As this is exactly what you @emph{don't} want, we named
2621 the tinc project after TINC.
2624 But in order to be ``immune'' to eavesdropping, you'll have to encrypt
2625 your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does
2626 exactly that: encrypt.
2627 Tinc by default uses blowfish encryption with 128 bit keys in CBC mode, 32 bit
2628 sequence numbers and 4 byte long message authentication codes to make sure
2629 eavesdroppers cannot get and cannot change any information at all from the
2630 packets they can intercept. The encryption algorithm and message authentication
2631 algorithm can be changed in the configuration. The length of the message
2632 authentication codes is also adjustable. The length of the key for the
2633 encryption algorithm is always the default length used by OpenSSL.
2636 * Authentication protocol::
2637 * Encryption of network packets::
2642 @c ==================================================================
2643 @node Authentication protocol
2644 @subsection Authentication protocol
2646 @cindex authentication
2647 A new scheme for authentication in tinc has been devised, which offers some
2648 improvements over the protocol used in 1.0pre2 and 1.0pre3. Explanation is
2658 --------------------------------------------------------------------------
2659 client <attempts connection>
2661 server <accepts connection>
2665 +-------> name of tinc daemon
2669 +-------> name of tinc daemon
2671 client META_KEY 5f0823a93e35b69e...7086ec7866ce582b
2672 \_________________________________/
2673 +-> RSAKEYLEN bits totally random string S1,
2674 encrypted with server's public RSA key
2676 server META_KEY 6ab9c1640388f8f0...45d1a07f8a672630
2677 \_________________________________/
2678 +-> RSAKEYLEN bits totally random string S2,
2679 encrypted with client's public RSA key
2682 - the client will symmetrically encrypt outgoing traffic using S1
2683 - the server will symmetrically encrypt outgoing traffic using S2
2685 client CHALLENGE da02add1817c1920989ba6ae2a49cecbda0
2686 \_________________________________/
2687 +-> CHALLEN bits totally random string H1
2689 server CHALLENGE 57fb4b2ccd70d6bb35a64c142f47e61d57f
2690 \_________________________________/
2691 +-> CHALLEN bits totally random string H2
2693 client CHAL_REPLY 816a86
2694 +-> 160 bits SHA1 of H2
2696 server CHAL_REPLY 928ffe
2697 +-> 160 bits SHA1 of H1
2699 After the correct challenge replies are received, both ends have proved
2700 their identity. Further information is exchanged.
2702 client ACK 655 123 0
2704 | +----> estimated weight
2705 +--------> listening port of client
2707 server ACK 655 321 0
2709 | +----> estimated weight
2710 +--------> listening port of server
2711 --------------------------------------------------------------------------
2714 This new scheme has several improvements, both in efficiency and security.
2716 First of all, the server sends exactly the same kind of messages over the wire
2717 as the client. The previous versions of tinc first authenticated the client,
2718 and then the server. This scheme even allows both sides to send their messages
2719 simultaneously, there is no need to wait for the other to send something first.
2720 This means that any calculations that need to be done upon sending or receiving
2721 a message can also be done in parallel. This is especially important when doing
2722 RSA encryption/decryption. Given that these calculations are the main part of
2723 the CPU time spent for the authentication, speed is improved by a factor 2.
2725 Second, only one RSA encrypted message is sent instead of two. This reduces the
2726 amount of information attackers can see (and thus use for a cryptographic
2727 attack). It also improves speed by a factor two, making the total speedup a
2730 Third, and most important:
2731 The symmetric cipher keys are exchanged first, the challenge is done
2732 afterwards. In the previous authentication scheme, because a man-in-the-middle
2733 could pass the challenge/chal_reply phase (by just copying the messages between
2734 the two real tinc daemons), but no information was exchanged that was really
2735 needed to read the rest of the messages, the challenge/chal_reply phase was of
2736 no real use. The man-in-the-middle was only stopped by the fact that only after
2737 the ACK messages were encrypted with the symmetric cipher. Potentially, it
2738 could even send it's own symmetric key to the server (if it knew the server's
2739 public key) and read some of the metadata the server would send it (it was
2740 impossible for the mitm to read actual network packets though). The new scheme
2741 however prevents this.
2743 This new scheme makes sure that first of all, symmetric keys are exchanged. The
2744 rest of the messages are then encrypted with the symmetric cipher. Then, each
2745 side can only read received messages if they have their private key. The
2746 challenge is there to let the other side know that the private key is really
2747 known, because a challenge reply can only be sent back if the challenge is
2748 decrypted correctly, and that can only be done with knowledge of the private
2751 Fourth: the first thing that is sent via the symmetric cipher encrypted
2752 connection is a totally random string, so that there is no known plaintext (for
2753 an attacker) in the beginning of the encrypted stream.
2756 @c ==================================================================
2757 @node Encryption of network packets
2758 @subsection Encryption of network packets
2761 A data packet can only be sent if the encryption key is known to both
2762 parties, and the connection is activated. If the encryption key is not
2763 known, a request is sent to the destination using the meta connection
2764 to retrieve it. The packet is stored in a queue while waiting for the
2768 The UDP packet containing the network packet from the VPN has the following layout:
2771 ... | IP header | UDP header | seqno | VPN packet | MAC | UDP trailer
2772 \___________________/\_____/
2774 V +---> digest algorithm
2775 Encrypted with symmetric cipher
2778 So, the entire VPN packet is encrypted using a symmetric cipher, including a 32 bits
2779 sequence number that is added in front of the actual VPN packet, to act as a unique
2780 IV for each packet and to prevent replay attacks. A message authentication code
2781 is added to the UDP packet to prevent alteration of packets. By default the
2782 first 4 bytes of the digest are used for this, but this can be changed using
2783 the MACLength configuration variable.
2785 @c ==================================================================
2786 @node Security issues
2787 @subsection Security issues
2789 In August 2000, we discovered the existence of a security hole in all versions
2790 of tinc up to and including 1.0pre2. This had to do with the way we exchanged
2791 keys. Since then, we have been working on a new authentication scheme to make
2792 tinc as secure as possible. The current version uses the OpenSSL library and
2793 uses strong authentication with RSA keys.
2795 On the 29th of December 2001, Jerome Etienne posted a security analysis of tinc
2796 1.0pre4. Due to a lack of sequence numbers and a message authentication code
2797 for each packet, an attacker could possibly disrupt certain network services or
2798 launch a denial of service attack by replaying intercepted packets. The current
2799 version adds sequence numbers and message authentication codes to prevent such
2802 On the 15th of September 2003, Peter Gutmann posted a security analysis of tinc
2803 1.0.1. He argues that the 32 bit sequence number used by tinc is not a good IV,
2804 that tinc's default length of 4 bytes for the MAC is too short, and he doesn't
2805 like tinc's use of RSA during authentication. We do not know of a security hole
2806 in this version of tinc, but tinc's security is not as strong as TLS or IPsec.
2807 We will address these issues in tinc 2.0.
2809 Cryptography is a hard thing to get right. We cannot make any
2810 guarantees. Time, review and feedback are the only things that can
2811 prove the security of any cryptographic product. If you wish to review
2812 tinc or give us feedback, you are stronly encouraged to do so.
2815 @c ==================================================================
2816 @node Platform specific information
2817 @chapter Platform specific information
2820 * Interface configuration::
2824 @c ==================================================================
2825 @node Interface configuration
2826 @section Interface configuration
2828 When configuring an interface, one normally assigns it an address and a
2829 netmask. The address uniquely identifies the host on the network attached to
2830 the interface. The netmask, combined with the address, forms a subnet. It is
2831 used to add a route to the routing table instructing the kernel to send all
2832 packets which fall into that subnet to that interface. Because all packets for
2833 the entire VPN should go to the virtual network interface used by tinc, the
2834 netmask should be such that it encompasses the entire VPN.
2838 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2840 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2841 @item Linux iproute2
2842 @tab @code{ip addr add} @var{address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2844 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2846 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2848 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2850 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2851 @item Darwin (MacOS/X)
2852 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2854 @tab @code{netsh interface ip set address} @var{interface} @code{static} @var{address} @var{netmask}
2859 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2861 @tab @code{ifconfig} @var{interface} @code{add} @var{address}@code{/}@var{prefixlength}
2863 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2865 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2867 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2869 @tab @code{ifconfig} @var{interface} @code{inet6 plumb up}
2871 @tab @code{ifconfig} @var{interface} @code{inet6 addif} @var{address} @var{address}
2872 @item Darwin (MacOS/X)
2873 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2875 @tab @code{netsh interface ipv6 add address} @var{interface} @code{static} @var{address}/@var{prefixlength}
2878 On some platforms, when running tinc in switch mode, the VPN interface must be set to tap mode with an ifconfig command:
2880 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2882 @tab @code{ifconfig} @var{interface} @code{link0}
2885 On Linux, it is possible to create a persistent tun/tap interface which will
2886 continue to exist even if tinc quit, although this is normally not required.
2887 It can be useful to set up a tun/tap interface owned by a non-root user, so
2888 tinc can be started without needing any root privileges at all.
2890 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2892 @tab @code{ip tuntap add dev} @var{interface} @code{mode} @var{tun|tap} @code{user} @var{username}
2895 @c ==================================================================
2899 In some cases it might be necessary to add more routes to the virtual network
2900 interface. There are two ways to indicate which interface a packet should go
2901 to, one is to use the name of the interface itself, another way is to specify
2902 the (local) address that is assigned to that interface (@var{local_address}). The
2903 former way is unambiguous and therefore preferable, but not all platforms
2906 Adding routes to IPv4 subnets:
2908 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2910 @tab @code{route add -net} @var{network_address} @code{netmask} @var{netmask} @var{interface}
2911 @item Linux iproute2
2912 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2914 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2916 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2918 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2920 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
2921 @item Darwin (MacOS/X)
2922 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2924 @tab @code{netsh routing ip add persistentroute} @var{network_address} @var{netmask} @var{interface} @var{local_address}
2927 Adding routes to IPv6 subnets:
2929 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2931 @tab @code{route add -A inet6} @var{network_address}@code{/}@var{prefixlength} @var{interface}
2932 @item Linux iproute2
2933 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2935 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2937 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
2939 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
2941 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
2942 @item Darwin (MacOS/X)
2945 @tab @code{netsh interface ipv6 add route} @var{network address}/@var{prefixlength} @var{interface}
2949 @c ==================================================================
2955 * Contact information::
2960 @c ==================================================================
2961 @node Contact information
2962 @section Contact information
2965 Tinc's website is at @url{http://www.tinc-vpn.org/},
2966 this server is located in the Netherlands.
2969 We have an IRC channel on the FreeNode and OFTC IRC networks. Connect to
2970 @uref{http://www.freenode.net/, irc.freenode.net}
2972 @uref{http://www.oftc.net/, irc.oftc.net}
2973 and join channel #tinc.
2976 @c ==================================================================
2981 @item Ivo Timmermans (zarq)
2982 @item Guus Sliepen (guus) (@email{guus@@tinc-vpn.org})
2985 We have received a lot of valuable input from users. With their help,
2986 tinc has become the flexible and robust tool that it is today. We have
2987 composed a list of contributions, in the file called @file{THANKS} in
2988 the source distribution.
2991 @c ==================================================================
2993 @unnumbered Concept Index
2995 @c ==================================================================
2999 @c ==================================================================