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{} 1998-2012 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{} 1998-2012 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 commands:
1519 tincctl -n @var{netname} export | ssh bar.example.org tincctl -n @var{netname} import
1520 ssh bar.example.org tincctl -n @var{netname} export | tincctl -n @var{netname} import
1523 You should repeat this for all nodes you ConnectTo, or which ConnectTo you.
1524 However, remember that you do not need to ConnectTo all nodes in the VPN;
1525 it is only necessary to create one or a few meta-connections,
1526 after the connections are made tinc will learn about all the other nodes in the VPN,
1527 and will automatically make other connections as necessary.
1530 @c ==================================================================
1531 @node Network interfaces
1532 @section Network interfaces
1534 Before tinc can start transmitting data over the tunnel, it must
1535 set up the virtual network interface.
1537 First, decide which IP addresses you want to have associated with these
1538 devices, and what network mask they must have.
1540 Tinc will open a virtual network device (@file{/dev/tun}, @file{/dev/tap0} or similar),
1541 which will also create a network interface called something like @samp{tun0}, @samp{tap0}.
1542 If you are using the Linux tun/tap driver, the network interface will by default have the same name as the @var{netname}.
1543 Under Windows you can change the name of the network interface from the Network Connections control panel.
1546 You can configure the network interface by putting ordinary ifconfig, route, and other commands
1547 to a script named @file{@value{sysconfdir}/tinc/@var{netname}/tinc-up}.
1548 When tinc starts, this script will be executed. When tinc exits, it will execute the script named
1549 @file{@value{sysconfdir}/tinc/@var{netname}/tinc-down}, but normally you don't need to create that script.
1550 You can manually open the script in an editor, or use the following command:
1553 tincctl -n @var{netname} edit tinc-up
1556 An example @file{tinc-up} script, that would be appropriate for the scenario in the previous section, is:
1560 ifconfig $INTERFACE 192.168.2.1 netmask 255.255.0.0
1561 ip addr add fec0:0:0:2::/48 dev $INTERFACE
1564 The first command gives the interface an IPv4 address and a netmask.
1565 The kernel will also automatically add an IPv4 route to this interface, so normally you don't need
1566 to add route commands to the @file{tinc-up} script.
1567 The kernel will also bring the interface up after this command.
1569 The netmask is the mask of the @emph{entire} VPN network, not just your
1571 The second command gives the interface an IPv6 address and netmask,
1572 which will also automatically add an IPv6 route.
1573 If you only want to use "ip addr" commands on Linux, don't forget that it doesn't bring the interface up, unlike ifconfig,
1574 so you need to add @samp{ip link set $INTERFACE up} in that case.
1576 The exact syntax of the ifconfig and route commands differs from platform to platform.
1577 You can look up the commands for setting addresses and adding routes in @ref{Platform specific information},
1578 but it is best to consult the manpages of those utilities on your platform.
1581 @c ==================================================================
1582 @node Example configuration
1583 @section Example configuration
1587 Imagine the following situation. Branch A of our example `company' wants to connect
1588 three branch offices in B, C and D using the Internet. All four offices
1589 have a 24/7 connection to the Internet.
1591 A is going to serve as the center of the network. B and C will connect
1592 to A, and D will connect to C. Each office will be assigned their own IP
1596 A: net 10.1.0.0 mask 255.255.0.0 gateway 10.1.54.1 internet IP 1.2.3.4
1597 B: net 10.2.0.0 mask 255.255.0.0 gateway 10.2.1.12 internet IP 2.3.4.5
1598 C: net 10.3.0.0 mask 255.255.0.0 gateway 10.3.69.254 internet IP 3.4.5.6
1599 D: net 10.4.0.0 mask 255.255.0.0 gateway 10.4.3.32 internet IP 4.5.6.7
1602 Here, ``gateway'' is the VPN IP address of the machine that is running the
1603 tincd, and ``internet IP'' is the IP address of the firewall, which does not
1604 need to run tincd, but it must do a port forwarding of TCP and UDP on port
1605 655 (unless otherwise configured).
1607 In this example, it is assumed that eth0 is the interface that points to
1608 the inner (physical) LAN of the office, although this could also be the
1609 same as the interface that leads to the Internet. The configuration of
1610 the real interface is also shown as a comment, to give you an idea of
1611 how these example host is set up. All branches use the netname `company'
1612 for this particular VPN.
1614 Each branch is set up using the @samp{tincctl init} and @samp{tincctl config} commands,
1615 here we just show the end results:
1617 @subsubheading For Branch A
1619 @emph{BranchA} would be configured like this:
1621 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1626 # Real interface of internal network:
1627 # ifconfig eth0 10.1.54.1 netmask 255.255.0.0
1629 ifconfig $INTERFACE 10.1.54.1 netmask 255.0.0.0
1632 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1638 On all hosts, @file{@value{sysconfdir}/tinc/company/hosts/BranchA} contains:
1641 Subnet = 10.1.0.0/16
1644 -----BEGIN RSA PUBLIC KEY-----
1646 -----END RSA PUBLIC KEY-----
1649 Note that the IP addresses of eth0 and the VPN interface are the same.
1650 This is quite possible, if you make sure that the netmasks of the interfaces are different.
1651 It is in fact recommended to give both real internal network interfaces and VPN interfaces the same IP address,
1652 since that will make things a lot easier to remember and set up.
1655 @subsubheading For Branch B
1657 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1662 # Real interface of internal network:
1663 # ifconfig eth0 10.2.43.8 netmask 255.255.0.0
1665 ifconfig $INTERFACE 10.2.1.12 netmask 255.0.0.0
1668 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1675 Note here that the internal address (on eth0) doesn't have to be the
1676 same as on the VPN interface. Also, ConnectTo is given so that this node will
1677 always try to connect to BranchA.
1679 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchB}:
1682 Subnet = 10.2.0.0/16
1685 -----BEGIN RSA PUBLIC KEY-----
1687 -----END RSA PUBLIC KEY-----
1691 @subsubheading For Branch C
1693 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1698 # Real interface of internal network:
1699 # ifconfig eth0 10.3.69.254 netmask 255.255.0.0
1701 ifconfig $INTERFACE 10.3.69.254 netmask 255.0.0.0
1704 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1711 C already has another daemon that runs on port 655, so they have to
1712 reserve another port for tinc. It knows the portnumber it has to listen on
1713 from it's own host configuration file.
1715 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchC}:
1719 Subnet = 10.3.0.0/16
1722 -----BEGIN RSA PUBLIC KEY-----
1724 -----END RSA PUBLIC KEY-----
1728 @subsubheading For Branch D
1730 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1735 # Real interface of internal network:
1736 # ifconfig eth0 10.4.3.32 netmask 255.255.0.0
1738 ifconfig $INTERFACE 10.4.3.32 netmask 255.0.0.0
1741 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1748 D will be connecting to C, which has a tincd running for this network on
1749 port 2000. It knows the port number from the host configuration file.
1751 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchD}:
1754 Subnet = 10.4.0.0/16
1757 -----BEGIN RSA PUBLIC KEY-----
1759 -----END RSA PUBLIC KEY-----
1762 @subsubheading Key files
1764 A, B, C and D all have their own public/private keypairs:
1766 The private RSA key is stored in @file{@value{sysconfdir}/tinc/company/rsa_key.priv},
1767 the private ECDSA key is stored in @file{@value{sysconfdir}/tinc/company/ecdsa_key.priv},
1768 and the public RSA and ECDSA keys are put into the host configuration file in the @file{@value{sysconfdir}/tinc/company/hosts/} directory.
1770 @subsubheading Starting
1772 After each branch has finished configuration and they have distributed
1773 the host configuration files amongst them, they can start their tinc daemons.
1774 They don't necessarily have to wait for the other branches to have started
1775 their daemons, tinc will try connecting until they are available.
1778 @c ==================================================================
1780 @chapter Running tinc
1782 If everything else is done, you can start tinc by typing the following command:
1785 tincctl -n @var{netname} start
1789 Tinc will detach from the terminal and continue to run in the background like a good daemon.
1790 If there are any problems however you can try to increase the debug level
1791 and look in the syslog to find out what the problems are.
1797 * Solving problems::
1799 * Sending bug reports::
1803 @c ==================================================================
1804 @node Runtime options
1805 @section Runtime options
1807 Besides the settings in the configuration file, tinc also accepts some
1808 command line options.
1810 @cindex command line
1811 @cindex runtime options
1815 @item -c, --config=@var{path}
1816 Read configuration options from the directory @var{path}. The default is
1817 @file{@value{sysconfdir}/tinc/@var{netname}/}.
1819 @item -D, --no-detach
1820 Don't fork and detach.
1821 This will also disable the automatic restart mechanism for fatal errors.
1824 @item -d, --debug=@var{level}
1825 Set debug level to @var{level}. The higher the debug level, the more gets
1826 logged. Everything goes via syslog.
1828 @item -n, --net=@var{netname}
1829 Use configuration for net @var{netname}.
1830 This will let tinc read all configuration files from
1831 @file{@value{sysconfdir}/tinc/@var{netname}/}.
1832 Specifying . for @var{netname} is the same as not specifying any @var{netname}.
1833 @xref{Multiple networks}.
1835 @item --pidfile=@var{filename}
1836 Store a cookie in @var{filename} which allows tincctl to authenticate.
1837 If unspecified, the default is
1838 @file{@value{localstatedir}/run/tinc.@var{netname}.pid}.
1840 @item -o, --option=[@var{HOST}.]@var{KEY}=@var{VALUE}
1841 Without specifying a @var{HOST}, this will set server configuration variable @var{KEY} to @var{VALUE}.
1842 If specified as @var{HOST}.@var{KEY}=@var{VALUE},
1843 this will set the host configuration variable @var{KEY} of the host named @var{HOST} to @var{VALUE}.
1844 This option can be used more than once to specify multiple configuration variables.
1847 Lock tinc into main memory.
1848 This will prevent sensitive data like shared private keys to be written to the system swap files/partitions.
1850 This option is not supported on all platforms.
1852 @item --logfile[=@var{file}]
1853 Write log entries to a file instead of to the system logging facility.
1854 If @var{file} is omitted, the default is @file{@value{localstatedir}/log/tinc.@var{netname}.log}.
1856 @item --bypass-security
1857 Disables encryption and authentication.
1858 Only useful for debugging.
1861 Change process root directory to the directory where the config file is
1862 located (@file{@value{sysconfdir}/tinc/@var{netname}/} as determined by
1863 -n/--net option or as given by -c/--config option), for added security.
1864 The chroot is performed after all the initialization is done, after
1865 writing pid files and opening network sockets.
1867 Note that this option alone does not do any good without -U/--user, below.
1869 Note also that tinc can't run scripts anymore (such as tinc-down or host-up),
1870 unless it's setup to be runnable inside chroot environment.
1872 This option is not supported on all platforms.
1873 @item -U, --user=@var{user}
1874 Switch to the given @var{user} after initialization, at the same time as
1875 chroot is performed (see --chroot above). With this option tinc drops
1876 privileges, for added security.
1878 This option is not supported on all platforms.
1881 Display a short reminder of these runtime options and terminate.
1884 Output version information and exit.
1888 @c ==================================================================
1893 You can also send the following signals to a running tincd process:
1899 Forces tinc to try to connect to all uplinks immediately.
1900 Usually tinc attempts to do this itself,
1901 but increases the time it waits between the attempts each time it failed,
1902 and if tinc didn't succeed to connect to an uplink the first time after it started,
1903 it defaults to the maximum time of 15 minutes.
1906 Partially rereads configuration files.
1907 Connections to hosts whose host config file are removed are closed.
1908 New outgoing connections specified in @file{tinc.conf} will be made.
1909 If the --logfile option is used, this will also close and reopen the log file,
1910 useful when log rotation is used.
1914 @c ==================================================================
1916 @section Debug levels
1918 @cindex debug levels
1919 The tinc daemon can send a lot of messages to the syslog.
1920 The higher the debug level, the more messages it will log.
1921 Each level inherits all messages of the previous level:
1927 This will log a message indicating tinc has started along with a version number.
1928 It will also log any serious error.
1931 This will log all connections that are made with other tinc daemons.
1934 This will log status and error messages from scripts and other tinc daemons.
1937 This will log all requests that are exchanged with other tinc daemons. These include
1938 authentication, key exchange and connection list updates.
1941 This will log a copy of everything received on the meta socket.
1944 This will log all network traffic over the virtual private network.
1948 @c ==================================================================
1949 @node Solving problems
1950 @section Solving problems
1952 If tinc starts without problems, but if the VPN doesn't work, you will have to find the cause of the problem.
1953 The first thing to do is to start tinc with a high debug level in the foreground,
1954 so you can directly see everything tinc logs:
1957 tincd -n @var{netname} -d5 -D
1960 If tinc does not log any error messages, then you might want to check the following things:
1963 @item @file{tinc-up} script
1964 Does this script contain the right commands?
1965 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.
1968 Does the Subnet (or Subnets) in the host configuration file of this host match the portion of the VPN that belongs to this host?
1970 @item Firewalls and NATs
1971 Do you have a firewall or a NAT device (a masquerading firewall or perhaps an ADSL router that performs masquerading)?
1972 If so, check that it allows TCP and UDP traffic on port 655.
1973 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.
1974 You can add @samp{TCPOnly = yes} to your host config file to force tinc to only use a single TCP connection,
1975 this works through most firewalls and NATs.
1980 @c ==================================================================
1981 @node Error messages
1982 @section Error messages
1984 What follows is a list of the most common error messages you might find in the logs.
1985 Some of them will only be visible if the debug level is high enough.
1988 @item Could not open /dev/tap0: No such device
1991 @item You forgot to `modprobe netlink_dev' or `modprobe ethertap'.
1992 @item You forgot to compile `Netlink device emulation' in the kernel.
1995 @item Can't write to /dev/net/tun: No such device
1998 @item You forgot to `modprobe tun'.
1999 @item You forgot to compile `Universal TUN/TAP driver' in the kernel.
2000 @item The tun device is located somewhere else in @file{/dev/}.
2003 @item Network address and prefix length do not match!
2006 @item The Subnet field must contain a @emph{network} address, trailing bits should be 0.
2007 @item If you only want to use one IP address, set the netmask to /32.
2010 @item Error reading RSA key file `rsa_key.priv': No such file or directory
2013 @item You forgot to create a public/private keypair.
2014 @item Specify the complete pathname to the private key file with the @samp{PrivateKeyFile} option.
2017 @item Warning: insecure file permissions for RSA private key file `rsa_key.priv'!
2020 @item The private key file is readable by users other than root.
2021 Use chmod to correct the file permissions.
2024 @item Creating metasocket failed: Address family not supported
2027 @item By default tinc tries to create both IPv4 and IPv6 sockets.
2028 On some platforms this might not be implemented.
2029 If the logs show @samp{Ready} later on, then at least one metasocket was created,
2030 and you can ignore this message.
2031 You can add @samp{AddressFamily = ipv4} to @file{tinc.conf} to prevent this from happening.
2034 @item Cannot route packet: unknown IPv4 destination 1.2.3.4
2037 @item You try to send traffic to a host on the VPN for which no Subnet is known.
2038 @item If it is a broadcast address (ending in .255), it probably is a samba server or a Windows host sending broadcast packets.
2042 @item Cannot route packet: ARP request for unknown address 1.2.3.4
2045 @item You try to send traffic to a host on the VPN for which no Subnet is known.
2048 @item Packet with destination 1.2.3.4 is looping back to us!
2051 @item Something is not configured right. Packets are being sent out to the
2052 virtual network device, but according to the Subnet directives in your host configuration
2053 file, those packets should go to your own host. Most common mistake is that
2054 you have a Subnet line in your host configuration file with a prefix length which is
2055 just as large as the prefix of the virtual network interface. The latter should in almost all
2056 cases be larger. Rethink your configuration.
2057 Note that you will only see this message if you specified a debug
2058 level of 5 or higher!
2059 @item Chances are that a @samp{Subnet = ...} line in the host configuration file of this tinc daemon is wrong.
2060 Change it to a subnet that is accepted locally by another interface,
2061 or if that is not the case, try changing the prefix length into /32.
2064 @item Node foo (1.2.3.4) is not reachable
2067 @item Node foo does not have a connection anymore, its tinc daemon is not running or its connection to the Internet is broken.
2070 @item Received UDP packet from unknown source 1.2.3.4 (port 12345)
2073 @item If you see this only sporadically, it is harmless and caused by a node sending packets using an old key.
2074 @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.
2075 You can add @samp{TCPOnly = yes} to host configuration files to force all VPN traffic to go over a TCP connection.
2078 @item Got bad/bogus/unauthorized REQUEST from foo (1.2.3.4 port 12345)
2081 @item Node foo does not have the right public/private keypair.
2082 Generate new keypairs and distribute them again.
2083 @item An attacker tries to gain access to your VPN.
2084 @item A network error caused corruption of metadata sent from foo.
2089 @c ==================================================================
2090 @node Sending bug reports
2091 @section Sending bug reports
2093 If you really can't find the cause of a problem, or if you suspect tinc is not working right,
2094 you can send us a bugreport, see @ref{Contact information}.
2095 Be sure to include the following information in your bugreport:
2098 @item A clear description of what you are trying to achieve and what the problem is.
2099 @item What platform (operating system, version, hardware architecture) and which version of tinc you use.
2100 @item If compiling tinc fails, a copy of @file{config.log} and the error messages you get.
2101 @item Otherwise, a copy of @file{tinc.conf}, @file{tinc-up} and all files in the @file{hosts/} directory.
2102 @item The output of the commands @samp{ifconfig -a} and @samp{route -n} (or @samp{netstat -rn} if that doesn't work).
2103 @item The output of any command that fails to work as it should (like ping or traceroute).
2106 @c ==================================================================
2107 @node Controlling tinc
2108 @chapter Controlling tinc
2110 You can control and inspect a running tincd through the tincctl
2111 command. A quick example:
2114 tincctl -n @var{netname} reload
2118 * tincctl runtime options::
2119 * tincctl environment variables::
2120 * tincctl commands::
2121 * tincctl examples::
2126 @c ==================================================================
2127 @node tincctl runtime options
2128 @section tincctl runtime options
2132 @item -c, --config=@var{path}
2133 Read configuration options from the directory @var{path}. The default is
2134 @file{@value{sysconfdir}/tinc/@var{netname}/}.
2136 @item -n, --net=@var{netname}
2137 Use configuration for net @var{netname}. @xref{Multiple networks}.
2139 @item --pidfile=@var{filename}
2140 Use the cookie from @var{filename} to authenticate with a running tinc daemon.
2141 If unspecified, the default is
2142 @file{@value{localstatedir}/run/tinc.@var{netname}.pid}.
2145 Display a short reminder of runtime options and commands, then terminate.
2148 Output version information and exit.
2152 @c ==================================================================
2153 @node tincctl environment variables
2154 @section tincctl environment variables
2159 If no netname is specified on the command line with the @option{-n} option,
2160 the value of this environment variable is used.
2163 @c ==================================================================
2164 @node tincctl commands
2165 @section tincctl commands
2170 @item init [@var{name}]
2171 Create initial configuration files and RSA and ECDSA keypairs with default length.
2172 If no @var{name} for this node is given, it will be asked for.
2174 @item config [get] @var{variable}
2175 Print the current value of configuration variable @var{variable}.
2176 If more than one variable with the same name exists,
2177 the value of each of them will be printed on a separate line.
2179 @item config [set] @var{variable} @var{value}
2180 Set configuration variable @var{variable} to the given @var{value}.
2181 All previously existing configuration variables with the same name are removed.
2182 To set a variable for a specific host, use the notation @var{host}.@var{variable}.
2184 @item config add @var{variable} @var{value}
2185 As above, but without removing any previously existing configuration variables.
2187 @item config del @var{variable} [@var{value}]
2188 Remove configuration variables with the same name and @var{value}.
2189 If no @var{value} is given, all configuration variables with the same name will be removed.
2191 @item edit @var{filename}
2192 Start an editor for the given configuration file.
2193 You do not need to specify the full path to the file.
2196 Export the host configuration file of the local node to standard output.
2199 Export all host configuration files to standard output.
2201 @item import [--force]
2202 Import host configuration file(s) generated by the tincctl export command from standard input.
2203 Already existing host configuration files are not overwritten unless the option --force is used.
2205 @item start [tincd options]
2206 Start @samp{tincd}, optionally with the given extra options.
2212 Restart @samp{tincd}.
2215 Partially rereads configuration files. Connections to hosts whose host
2216 config files are removed are closed. New outgoing connections specified
2217 in @file{tinc.conf} will be made.
2220 Shows the PID of the currently running @samp{tincd}.
2222 @item generate-keys [@var{bits}]
2223 Generate public/private keypair of @var{bits} length. If @var{bits} is not specified,
2224 1024 is the default. tinc will ask where you want to store the files,
2225 but will default to the configuration directory (you can use the -c or -n
2228 @item dump [reachable] nodes
2229 Dump a list of all known nodes in the VPN.
2230 If the reachable keyword is used, only lists reachable nodes.
2233 Dump a list of all known connections in the VPN.
2236 Dump a list of all known subnets in the VPN.
2238 @item dump connections
2239 Dump a list of all meta connections with ourself.
2241 @item dump graph | digraph
2242 Dump a graph of the VPN in dotty format.
2243 Nodes are colored according to their reachability:
2244 red nodes are unreachable, orange nodes are indirectly reachable, green nodes are directly reachable.
2245 Black nodes are either directly or indirectly reachable, but direct reachability has not been tried yet.
2247 @item info @var{node} | @var{subnet} | @var{address}
2248 Show information about a particular @var{node}, @var{subnet} or @var{address}.
2249 If an @var{address} is given, any matching subnet will be shown.
2252 Purges all information remembered about unreachable nodes.
2254 @item debug @var{level}
2255 Sets debug level to @var{level}.
2257 @item log [@var{level}]
2258 Capture log messages from a running tinc daemon.
2259 An optional debug level can be given that will be applied only for log messages sent to tincctl.
2262 Forces tinc to try to connect to all uplinks immediately.
2263 Usually tinc attempts to do this itself,
2264 but increases the time it waits between the attempts each time it failed,
2265 and if tinc didn't succeed to connect to an uplink the first time after it started,
2266 it defaults to the maximum time of 15 minutes.
2268 @item disconnect @var{node}
2269 Closes the meta connection with the given @var{node}.
2272 If tincctl is compiled with libcurses support, this will display live traffic statistics for all the known nodes,
2273 similar to the UNIX top command.
2274 See below for more information.
2277 Dump VPN traffic going through the local tinc node in pcap-savefile format to standard output,
2278 from where it can be redirected to a file or piped through a program that can parse it directly,
2283 @c ==================================================================
2284 @node tincctl examples
2285 @section tincctl examples
2287 Examples of some commands:
2290 tincctl -n vpn dump graph | circo -Txlib
2291 tincctl -n vpn pcap | tcpdump -r -
2295 Example of configuring tinc using tincctl:
2298 tincctl -n vpn init foo
2299 tincctl -n vpn config Subnet 192.168.1.0/24
2300 tincctl -n vpn config bar.Address bar.example.com
2301 tincctl -n vpn config ConnectTo bar
2302 tincctl -n vpn export | gpg --clearsign | mail -s "My config" vpnmaster@@example.com
2305 @c ==================================================================
2307 @section tincctl top
2309 The top command connects to a running tinc daemon and repeatedly queries its per-node traffic counters.
2310 It displays a list of all the known nodes in the left-most column,
2311 and the amount of bytes and packets read from and sent to each node in the other columns.
2312 By default, the information is updated every second.
2313 The behaviour of the top command can be changed using the following keys:
2318 Change the interval between updates.
2319 After pressing the @key{s} key, enter the desired interval in seconds, followed by enter.
2320 Fractional seconds are honored.
2321 Intervals lower than 0.1 seconds are not allowed.
2324 Toggle between displaying current traffic rates (in packets and bytes per second)
2325 and cummulative traffic (total packets and bytes since the tinc daemon started).
2328 Sort the list of nodes by name.
2331 Sort the list of nodes by incoming amount of bytes.
2334 Sort the list of nodes by incoming amount of packets.
2337 Sort the list of nodes by outgoing amount of bytes.
2340 Sort the list of nodes by outgoing amount of packets.
2343 Sort the list of nodes by sum of incoming and outgoing amount of bytes.
2346 Sort the list of nodes by sum of incoming and outgoing amount of packets.
2349 Show amount of traffic in bytes.
2352 Show amount of traffic in kilobytes.
2355 Show amount of traffic in megabytes.
2358 Show amount of traffic in gigabytes.
2366 @c ==================================================================
2367 @node Technical information
2368 @chapter Technical information
2373 * The meta-protocol::
2378 @c ==================================================================
2379 @node The connection
2380 @section The connection
2383 Tinc is a daemon that takes VPN data and transmit that to another host
2384 computer over the existing Internet infrastructure.
2388 * The meta-connection::
2392 @c ==================================================================
2393 @node The UDP tunnel
2394 @subsection The UDP tunnel
2396 @cindex virtual network device
2398 The data itself is read from a character device file, the so-called
2399 @emph{virtual network device}. This device is associated with a network
2400 interface. Any data sent to this interface can be read from the device,
2401 and any data written to the device gets sent from the interface.
2402 There are two possible types of virtual network devices:
2403 `tun' style, which are point-to-point devices which can only handle IPv4 and/or IPv6 packets,
2404 and `tap' style, which are Ethernet devices and handle complete Ethernet frames.
2406 So when tinc reads an Ethernet frame from the device, it determines its
2407 type. When tinc is in it's default routing mode, it can handle IPv4 and IPv6
2408 packets. Depending on the Subnet lines, it will send the packets off to their destination IP address.
2409 In the `switch' and `hub' mode, tinc will use broadcasts and MAC address discovery
2410 to deduce the destination of the packets.
2411 Since the latter modes only depend on the link layer information,
2412 any protocol that runs over Ethernet is supported (for instance IPX and Appletalk).
2413 However, only `tap' style devices provide this information.
2415 After the destination has been determined,
2416 the packet will be compressed (optionally),
2417 a sequence number will be added to the packet,
2418 the packet will then be encrypted
2419 and a message authentication code will be appended.
2421 @cindex encapsulating
2423 When that is done, time has come to actually transport the
2424 packet to the destination computer. We do this by sending the packet
2425 over an UDP connection to the destination host. This is called
2426 @emph{encapsulating}, the VPN packet (though now encrypted) is
2427 encapsulated in another IP datagram.
2429 When the destination receives this packet, the same thing happens, only
2430 in reverse. So it checks the message authentication code, decrypts the contents of the UDP datagram,
2431 checks the sequence number
2432 and writes the decrypted information to its own virtual network device.
2434 If the virtual network device is a `tun' device (a point-to-point tunnel),
2435 there is no problem for the kernel to accept a packet.
2436 However, if it is a `tap' device (this is the only available type on FreeBSD),
2437 the destination MAC address must match that of the virtual network interface.
2438 If tinc is in it's default routing mode, ARP does not work, so the correct destination MAC
2439 can not be known by the sending host.
2440 Tinc solves this by letting the receiving end detect the MAC address of its own virtual network interface
2441 and overwriting the destination MAC address of the received packet.
2443 In switch or hub modes ARP does work so the sender already knows the correct destination MAC address.
2444 In those modes every interface should have a unique MAC address, so make sure they are not the same.
2445 Because switch and hub modes rely on MAC addresses to function correctly,
2446 these modes cannot be used on the following operating systems which don't have a `tap' style virtual network device:
2447 OpenBSD, NetBSD, Darwin and Solaris.
2450 @c ==================================================================
2451 @node The meta-connection
2452 @subsection The meta-connection
2454 Having only a UDP connection available is not enough. Though suitable
2455 for transmitting data, we want to be able to reliably send other
2456 information, such as routing and session key information to somebody.
2459 TCP is a better alternative, because it already contains protection
2460 against information being lost, unlike UDP.
2462 So we establish two connections. One for the encrypted VPN data, and one
2463 for other information, the meta-data. Hence, we call the second
2464 connection the meta-connection. We can now be sure that the
2465 meta-information doesn't get lost on the way to another computer.
2467 @cindex data-protocol
2468 @cindex meta-protocol
2469 Like with any communication, we must have a protocol, so that everybody
2470 knows what everything stands for, and how she should react. Because we
2471 have two connections, we also have two protocols. The protocol used for
2472 the UDP data is the ``data-protocol,'' the other one is the
2475 The reason we don't use TCP for both protocols is that UDP is much
2476 better for encapsulation, even while it is less reliable. The real
2477 problem is that when TCP would be used to encapsulate a TCP stream
2478 that's on the private network, for every packet sent there would be
2479 three ACKs sent instead of just one. Furthermore, if there would be
2480 a timeout, both TCP streams would sense the timeout, and both would
2481 start re-sending packets.
2484 @c ==================================================================
2485 @node The meta-protocol
2486 @section The meta-protocol
2488 The meta protocol is used to tie all tinc daemons together, and
2489 exchange information about which tinc daemon serves which virtual
2492 The meta protocol consists of requests that can be sent to the other
2493 side. Each request has a unique number and several parameters. All
2494 requests are represented in the standard ASCII character set. It is
2495 possible to use tools such as telnet or netcat to connect to a tinc
2496 daemon started with the --bypass-security option
2497 and to read and write requests by hand, provided that one
2498 understands the numeric codes sent.
2500 The authentication scheme is described in @ref{Authentication protocol}. After a
2501 successful authentication, the server and the client will exchange all the
2502 information about other tinc daemons and subnets they know of, so that both
2503 sides (and all the other tinc daemons behind them) have their information
2510 ------------------------------------------------------------------
2511 ADD_EDGE node1 node2 21.32.43.54 655 222 0
2512 | | | | | +-> options
2513 | | | | +----> weight
2514 | | | +--------> UDP port of node2
2515 | | +----------------> real address of node2
2516 | +-------------------------> name of destination node
2517 +-------------------------------> name of source node
2519 ADD_SUBNET node 192.168.1.0/24
2520 | | +--> prefixlength
2521 | +--------> network address
2522 +------------------> owner of this subnet
2523 ------------------------------------------------------------------
2526 The ADD_EDGE messages are to inform other tinc daemons that a connection between
2527 two nodes exist. The address of the destination node is available so that
2528 VPN packets can be sent directly to that node.
2530 The ADD_SUBNET messages inform other tinc daemons that certain subnets belong
2531 to certain nodes. tinc will use it to determine to which node a VPN packet has
2538 ------------------------------------------------------------------
2539 DEL_EDGE node1 node2
2540 | +----> name of destination node
2541 +----------> name of source node
2543 DEL_SUBNET node 192.168.1.0/24
2544 | | +--> prefixlength
2545 | +--------> network address
2546 +------------------> owner of this subnet
2547 ------------------------------------------------------------------
2550 In case a connection between two daemons is closed or broken, DEL_EDGE messages
2551 are sent to inform the other daemons of that fact. Each daemon will calculate a
2552 new route to the the daemons, or mark them unreachable if there isn't any.
2559 ------------------------------------------------------------------
2560 REQ_KEY origin destination
2561 | +--> name of the tinc daemon it wants the key from
2562 +----------> name of the daemon that wants the key
2564 ANS_KEY origin destination 4ae0b0a82d6e0078 91 64 4
2565 | | \______________/ | | +--> MAC length
2566 | | | | +-----> digest algorithm
2567 | | | +--------> cipher algorithm
2568 | | +--> 128 bits key
2569 | +--> name of the daemon that wants the key
2570 +----------> name of the daemon that uses this key
2573 +--> daemon that has changed it's packet key
2574 ------------------------------------------------------------------
2577 The keys used to encrypt VPN packets are not sent out directly. This is
2578 because it would generate a lot of traffic on VPNs with many daemons, and
2579 chances are that not every tinc daemon will ever send a packet to every
2580 other daemon. Instead, if a daemon needs a key it sends a request for it
2581 via the meta connection of the nearest hop in the direction of the
2588 ------------------------------------------------------------------
2591 ------------------------------------------------------------------
2594 There is also a mechanism to check if hosts are still alive. Since network
2595 failures or a crash can cause a daemon to be killed without properly
2596 shutting down the TCP connection, this is necessary to keep an up to date
2597 connection list. PINGs are sent at regular intervals, except when there
2598 is also some other traffic. A little bit of salt (random data) is added
2599 with each PING and PONG message, to make sure that long sequences of PING/PONG
2600 messages without any other traffic won't result in known plaintext.
2602 This basically covers what is sent over the meta connection by tinc.
2605 @c ==================================================================
2611 Tinc got its name from ``TINC,'' short for @emph{There Is No Cabal}; the
2612 alleged Cabal was/is an organisation that was said to keep an eye on the
2613 entire Internet. As this is exactly what you @emph{don't} want, we named
2614 the tinc project after TINC.
2617 But in order to be ``immune'' to eavesdropping, you'll have to encrypt
2618 your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does
2619 exactly that: encrypt.
2620 Tinc by default uses blowfish encryption with 128 bit keys in CBC mode, 32 bit
2621 sequence numbers and 4 byte long message authentication codes to make sure
2622 eavesdroppers cannot get and cannot change any information at all from the
2623 packets they can intercept. The encryption algorithm and message authentication
2624 algorithm can be changed in the configuration. The length of the message
2625 authentication codes is also adjustable. The length of the key for the
2626 encryption algorithm is always the default length used by OpenSSL.
2629 * Authentication protocol::
2630 * Encryption of network packets::
2635 @c ==================================================================
2636 @node Authentication protocol
2637 @subsection Authentication protocol
2639 @cindex authentication
2640 A new scheme for authentication in tinc has been devised, which offers some
2641 improvements over the protocol used in 1.0pre2 and 1.0pre3. Explanation is
2651 --------------------------------------------------------------------------
2652 client <attempts connection>
2654 server <accepts connection>
2658 +-------> name of tinc daemon
2662 +-------> name of tinc daemon
2664 client META_KEY 5f0823a93e35b69e...7086ec7866ce582b
2665 \_________________________________/
2666 +-> RSAKEYLEN bits totally random string S1,
2667 encrypted with server's public RSA key
2669 server META_KEY 6ab9c1640388f8f0...45d1a07f8a672630
2670 \_________________________________/
2671 +-> RSAKEYLEN bits totally random string S2,
2672 encrypted with client's public RSA key
2675 - the client will symmetrically encrypt outgoing traffic using S1
2676 - the server will symmetrically encrypt outgoing traffic using S2
2678 client CHALLENGE da02add1817c1920989ba6ae2a49cecbda0
2679 \_________________________________/
2680 +-> CHALLEN bits totally random string H1
2682 server CHALLENGE 57fb4b2ccd70d6bb35a64c142f47e61d57f
2683 \_________________________________/
2684 +-> CHALLEN bits totally random string H2
2686 client CHAL_REPLY 816a86
2687 +-> 160 bits SHA1 of H2
2689 server CHAL_REPLY 928ffe
2690 +-> 160 bits SHA1 of H1
2692 After the correct challenge replies are received, both ends have proved
2693 their identity. Further information is exchanged.
2695 client ACK 655 123 0
2697 | +----> estimated weight
2698 +--------> listening port of client
2700 server ACK 655 321 0
2702 | +----> estimated weight
2703 +--------> listening port of server
2704 --------------------------------------------------------------------------
2707 This new scheme has several improvements, both in efficiency and security.
2709 First of all, the server sends exactly the same kind of messages over the wire
2710 as the client. The previous versions of tinc first authenticated the client,
2711 and then the server. This scheme even allows both sides to send their messages
2712 simultaneously, there is no need to wait for the other to send something first.
2713 This means that any calculations that need to be done upon sending or receiving
2714 a message can also be done in parallel. This is especially important when doing
2715 RSA encryption/decryption. Given that these calculations are the main part of
2716 the CPU time spent for the authentication, speed is improved by a factor 2.
2718 Second, only one RSA encrypted message is sent instead of two. This reduces the
2719 amount of information attackers can see (and thus use for a cryptographic
2720 attack). It also improves speed by a factor two, making the total speedup a
2723 Third, and most important:
2724 The symmetric cipher keys are exchanged first, the challenge is done
2725 afterwards. In the previous authentication scheme, because a man-in-the-middle
2726 could pass the challenge/chal_reply phase (by just copying the messages between
2727 the two real tinc daemons), but no information was exchanged that was really
2728 needed to read the rest of the messages, the challenge/chal_reply phase was of
2729 no real use. The man-in-the-middle was only stopped by the fact that only after
2730 the ACK messages were encrypted with the symmetric cipher. Potentially, it
2731 could even send it's own symmetric key to the server (if it knew the server's
2732 public key) and read some of the metadata the server would send it (it was
2733 impossible for the mitm to read actual network packets though). The new scheme
2734 however prevents this.
2736 This new scheme makes sure that first of all, symmetric keys are exchanged. The
2737 rest of the messages are then encrypted with the symmetric cipher. Then, each
2738 side can only read received messages if they have their private key. The
2739 challenge is there to let the other side know that the private key is really
2740 known, because a challenge reply can only be sent back if the challenge is
2741 decrypted correctly, and that can only be done with knowledge of the private
2744 Fourth: the first thing that is sent via the symmetric cipher encrypted
2745 connection is a totally random string, so that there is no known plaintext (for
2746 an attacker) in the beginning of the encrypted stream.
2749 @c ==================================================================
2750 @node Encryption of network packets
2751 @subsection Encryption of network packets
2754 A data packet can only be sent if the encryption key is known to both
2755 parties, and the connection is activated. If the encryption key is not
2756 known, a request is sent to the destination using the meta connection
2757 to retrieve it. The packet is stored in a queue while waiting for the
2761 The UDP packet containing the network packet from the VPN has the following layout:
2764 ... | IP header | UDP header | seqno | VPN packet | MAC | UDP trailer
2765 \___________________/\_____/
2767 V +---> digest algorithm
2768 Encrypted with symmetric cipher
2771 So, the entire VPN packet is encrypted using a symmetric cipher, including a 32 bits
2772 sequence number that is added in front of the actual VPN packet, to act as a unique
2773 IV for each packet and to prevent replay attacks. A message authentication code
2774 is added to the UDP packet to prevent alteration of packets. By default the
2775 first 4 bytes of the digest are used for this, but this can be changed using
2776 the MACLength configuration variable.
2778 @c ==================================================================
2779 @node Security issues
2780 @subsection Security issues
2782 In August 2000, we discovered the existence of a security hole in all versions
2783 of tinc up to and including 1.0pre2. This had to do with the way we exchanged
2784 keys. Since then, we have been working on a new authentication scheme to make
2785 tinc as secure as possible. The current version uses the OpenSSL library and
2786 uses strong authentication with RSA keys.
2788 On the 29th of December 2001, Jerome Etienne posted a security analysis of tinc
2789 1.0pre4. Due to a lack of sequence numbers and a message authentication code
2790 for each packet, an attacker could possibly disrupt certain network services or
2791 launch a denial of service attack by replaying intercepted packets. The current
2792 version adds sequence numbers and message authentication codes to prevent such
2795 On the 15th of September 2003, Peter Gutmann posted a security analysis of tinc
2796 1.0.1. He argues that the 32 bit sequence number used by tinc is not a good IV,
2797 that tinc's default length of 4 bytes for the MAC is too short, and he doesn't
2798 like tinc's use of RSA during authentication. We do not know of a security hole
2799 in this version of tinc, but tinc's security is not as strong as TLS or IPsec.
2800 We will address these issues in tinc 2.0.
2802 Cryptography is a hard thing to get right. We cannot make any
2803 guarantees. Time, review and feedback are the only things that can
2804 prove the security of any cryptographic product. If you wish to review
2805 tinc or give us feedback, you are stronly encouraged to do so.
2808 @c ==================================================================
2809 @node Platform specific information
2810 @chapter Platform specific information
2813 * Interface configuration::
2817 @c ==================================================================
2818 @node Interface configuration
2819 @section Interface configuration
2821 When configuring an interface, one normally assigns it an address and a
2822 netmask. The address uniquely identifies the host on the network attached to
2823 the interface. The netmask, combined with the address, forms a subnet. It is
2824 used to add a route to the routing table instructing the kernel to send all
2825 packets which fall into that subnet to that interface. Because all packets for
2826 the entire VPN should go to the virtual network interface used by tinc, the
2827 netmask should be such that it encompasses the entire VPN.
2831 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2833 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2834 @item Linux iproute2
2835 @tab @code{ip addr add} @var{address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2837 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2839 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2841 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2843 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2844 @item Darwin (MacOS/X)
2845 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
2847 @tab @code{netsh interface ip set address} @var{interface} @code{static} @var{address} @var{netmask}
2852 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2854 @tab @code{ifconfig} @var{interface} @code{add} @var{address}@code{/}@var{prefixlength}
2856 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2858 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2860 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2862 @tab @code{ifconfig} @var{interface} @code{inet6 plumb up}
2864 @tab @code{ifconfig} @var{interface} @code{inet6 addif} @var{address} @var{address}
2865 @item Darwin (MacOS/X)
2866 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
2868 @tab @code{netsh interface ipv6 add address} @var{interface} @code{static} @var{address}/@var{prefixlength}
2871 On some platforms, when running tinc in switch mode, the VPN interface must be set to tap mode with an ifconfig command:
2873 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2875 @tab @code{ifconfig} @var{interface} @code{link0}
2878 On Linux, it is possible to create a persistent tun/tap interface which will
2879 continue to exist even if tinc quit, although this is normally not required.
2880 It can be useful to set up a tun/tap interface owned by a non-root user, so
2881 tinc can be started without needing any root privileges at all.
2883 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2885 @tab @code{ip tuntap add dev} @var{interface} @code{mode} @var{tun|tap} @code{user} @var{username}
2888 @c ==================================================================
2892 In some cases it might be necessary to add more routes to the virtual network
2893 interface. There are two ways to indicate which interface a packet should go
2894 to, one is to use the name of the interface itself, another way is to specify
2895 the (local) address that is assigned to that interface (@var{local_address}). The
2896 former way is unambiguous and therefore preferable, but not all platforms
2899 Adding routes to IPv4 subnets:
2901 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2903 @tab @code{route add -net} @var{network_address} @code{netmask} @var{netmask} @var{interface}
2904 @item Linux iproute2
2905 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2907 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2909 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2911 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2913 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
2914 @item Darwin (MacOS/X)
2915 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2917 @tab @code{netsh routing ip add persistentroute} @var{network_address} @var{netmask} @var{interface} @var{local_address}
2920 Adding routes to IPv6 subnets:
2922 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
2924 @tab @code{route add -A inet6} @var{network_address}@code{/}@var{prefixlength} @var{interface}
2925 @item Linux iproute2
2926 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
2928 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
2930 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
2932 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
2934 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
2935 @item Darwin (MacOS/X)
2938 @tab @code{netsh interface ipv6 add route} @var{network address}/@var{prefixlength} @var{interface}
2942 @c ==================================================================
2948 * Contact information::
2953 @c ==================================================================
2954 @node Contact information
2955 @section Contact information
2958 Tinc's website is at @url{http://www.tinc-vpn.org/},
2959 this server is located in the Netherlands.
2962 We have an IRC channel on the FreeNode and OFTC IRC networks. Connect to
2963 @uref{http://www.freenode.net/, irc.freenode.net}
2965 @uref{http://www.oftc.net/, irc.oftc.net}
2966 and join channel #tinc.
2969 @c ==================================================================
2974 @item Ivo Timmermans (zarq)
2975 @item Guus Sliepen (guus) (@email{guus@@tinc-vpn.org})
2978 We have received a lot of valuable input from users. With their help,
2979 tinc has become the flexible and robust tool that it is today. We have
2980 composed a list of contributions, in the file called @file{THANKS} in
2981 the source distribution.
2984 @c ==================================================================
2986 @unnumbered Concept Index
2988 @c ==================================================================
2992 @c ==================================================================