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{} 1998-2014 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.
39 @subtitle Setting up a Virtual Private Network with tinc
40 @author Ivo Timmermans and Guus Sliepen
43 @vskip 0pt plus 1filll
44 This is the info manual for @value{PACKAGE} version @value{VERSION}, a Virtual Private Network daemon.
46 Copyright @copyright{} 1998-2014 Ivo Timmermans,
47 Guus Sliepen <guus@@tinc-vpn.org> and
48 Wessel Dankers <wsl@@tinc-vpn.org>.
50 Permission is granted to make and distribute verbatim copies of this
51 manual provided the copyright notice and this permission notice are
52 preserved on all copies.
54 Permission is granted to copy and distribute modified versions of this
55 manual under the conditions for verbatim copying, provided that the
56 entire resulting derived work is distributed under the terms of a
57 permission notice identical to this one.
62 @c ==================================================================
73 * Technical information::
74 * Platform specific information::
76 * Concept Index:: All used terms explained
80 @c ==================================================================
85 Tinc is a Virtual Private Network (VPN) daemon that uses tunneling and
86 encryption to create a secure private network between hosts on the
89 Because the tunnel appears to the IP level network code as a normal
90 network device, there is no need to adapt any existing software.
91 The encrypted tunnels allows VPN sites to share information with each other
92 over the Internet without exposing any information to others.
94 This document is the manual for tinc. Included are chapters on how to
95 configure your computer to use tinc, as well as the configuration
96 process of tinc itself.
99 * Virtual Private Networks::
101 * Supported platforms::
104 @c ==================================================================
105 @node Virtual Private Networks
106 @section Virtual Private Networks
109 A Virtual Private Network or VPN is a network that can only be accessed
110 by a few elected computers that participate. This goal is achievable in
111 more than just one way.
114 Private networks can consist of a single stand-alone Ethernet LAN. Or
115 even two computers hooked up using a null-modem cable. In these cases,
117 obvious that the network is @emph{private}, no one can access it from the
118 outside. But if your computers are linked to the Internet, the network
119 is not private anymore, unless one uses firewalls to block all private
120 traffic. But then, there is no way to send private data to trusted
121 computers on the other end of the Internet.
124 This problem can be solved by using @emph{virtual} networks. Virtual
125 networks can live on top of other networks, but they use encapsulation to
126 keep using their private address space so they do not interfere with
127 the Internet. Mostly, virtual networks appear like a single LAN, even though
128 they can span the entire world. But virtual networks can't be secured
129 by using firewalls, because the traffic that flows through it has to go
130 through the Internet, where other people can look at it.
132 As is the case with either type of VPN, anybody could eavesdrop. Or
133 worse, alter data. Hence it's probably advisable to encrypt the data
134 that flows over the network.
136 When one introduces encryption, we can form a true VPN. Other people may
137 see encrypted traffic, but if they don't know how to decipher it (they
138 need to know the key for that), they cannot read the information that flows
139 through the VPN. This is what tinc was made for.
142 @c ==================================================================
147 I really don't quite remember what got us started, but it must have been
148 Guus' idea. He wrote a simple implementation (about 50 lines of C) that
149 used the ethertap device that Linux knows of since somewhere
150 about kernel 2.1.60. It didn't work immediately and he improved it a
151 bit. At this stage, the project was still simply called "vpnd".
153 Since then, a lot has changed---to say the least.
156 Tinc now supports encryption, it consists of a single daemon (tincd) for
157 both the receiving and sending end, it has become largely
158 runtime-configurable---in short, it has become a full-fledged
159 professional package.
161 @cindex traditional VPNs
163 Tinc also allows more than two sites to connect to eachother and form a single VPN.
164 Traditionally VPNs are created by making tunnels, which only have two endpoints.
165 Larger VPNs with more sites are created by adding more tunnels.
166 Tinc takes another approach: only endpoints are specified,
167 the software itself will take care of creating the tunnels.
168 This allows for easier configuration and improved scalability.
170 A lot can---and will be---changed. We have a number of things that we would like to
171 see in the future releases of tinc. Not everything will be available in
172 the near future. Our first objective is to make tinc work perfectly as
173 it stands, and then add more advanced features.
175 Meanwhile, we're always open-minded towards new ideas. And we're
179 @c ==================================================================
180 @node Supported platforms
181 @section Supported platforms
184 Tinc has been verified to work under Linux, FreeBSD, OpenBSD, NetBSD, MacOS/X (Darwin), Solaris, and Windows (both natively and in a Cygwin environment),
185 with various hardware architectures. These are some of the platforms
186 that are supported by the universal tun/tap device driver or other virtual network device drivers.
187 Without such a driver, tinc will most
188 likely compile and run, but it will not be able to send or receive data
192 For an up to date list of supported platforms, please check the list on
194 @uref{http://www.tinc-vpn.org/platforms/}.
202 @c Preparing your system
209 @c ==================================================================
211 @chapter Preparations
213 This chapter contains information on how to prepare your system to
217 * Configuring the kernel::
222 @c ==================================================================
223 @node Configuring the kernel
224 @section Configuring the kernel
227 * Configuration of Linux kernels::
228 * Configuration of FreeBSD kernels::
229 * Configuration of OpenBSD kernels::
230 * Configuration of NetBSD kernels::
231 * Configuration of Solaris kernels::
232 * Configuration of Darwin (MacOS/X) kernels::
233 * Configuration of Windows::
237 @c ==================================================================
238 @node Configuration of Linux kernels
239 @subsection Configuration of Linux kernels
241 @cindex Universal tun/tap
242 For tinc to work, you need a kernel that supports the Universal tun/tap device.
243 Most distributions come with kernels that already support this.
244 Here are the options you have to turn on when configuring a new kernel:
247 Code maturity level options
248 [*] Prompt for development and/or incomplete code/drivers
249 Network device support
250 <M> Universal tun/tap device driver support
253 It's not necessary to compile this driver as a module, even if you are going to
254 run more than one instance of tinc.
256 If you decide to build the tun/tap driver as a kernel module, add these lines
257 to @file{/etc/modules.conf}:
260 alias char-major-10-200 tun
264 @c ==================================================================
265 @node Configuration of FreeBSD kernels
266 @subsection Configuration of FreeBSD kernels
268 For FreeBSD version 4.1 and higher, tun and tap drivers are included in the default kernel configuration.
269 The tap driver can be loaded with @code{kldload if_tap}, or by adding @code{if_tap_load="YES"} to @file{/boot/loader.conf}.
272 @c ==================================================================
273 @node Configuration of OpenBSD kernels
274 @subsection Configuration of OpenBSD kernels
276 For OpenBSD version 2.9 and higher,
277 the tun driver is included in the default kernel configuration.
278 There is also a kernel patch from @uref{http://diehard.n-r-g.com/stuff/openbsd/}
279 which adds a tap device to OpenBSD which should work with tinc,
280 but with recent versions of OpenBSD,
281 a tun device can act as a tap device by setting the link0 option with ifconfig.
284 @c ==================================================================
285 @node Configuration of NetBSD kernels
286 @subsection Configuration of NetBSD kernels
288 For NetBSD version 1.5.2 and higher,
289 the tun driver is included in the default kernel configuration.
291 Tunneling IPv6 may not work on NetBSD's tun device.
294 @c ==================================================================
295 @node Configuration of Solaris kernels
296 @subsection Configuration of Solaris kernels
298 For Solaris 8 (SunOS 5.8) and higher,
299 the tun driver may or may not be included in the default kernel configuration.
300 If it isn't, the source can be downloaded from @uref{http://vtun.sourceforge.net/tun/}.
301 For x86 and sparc64 architectures, precompiled versions can be found at @uref{http://www.monkey.org/~dugsong/fragroute/}.
302 If the @file{net/if_tun.h} header file is missing, install it from the source package.
305 @c ==================================================================
306 @node Configuration of Darwin (MacOS/X) kernels
307 @subsection Configuration of Darwin (MacOS/X) kernels
309 Tinc on Darwin relies on a tunnel driver for its data acquisition from the kernel.
310 Tinc supports either the driver from @uref{http://tuntaposx.sourceforge.net/},
311 which supports both tun and tap style devices,
312 and also the driver from from @uref{http://chrisp.de/en/projects/tunnel.html}.
313 The former driver is recommended.
314 The tunnel driver must be loaded before starting tinc with the following command:
321 @c ==================================================================
322 @node Configuration of Windows
323 @subsection Configuration of Windows
325 You will need to install the latest TAP-Win32 driver from OpenVPN.
326 You can download it from @uref{http://openvpn.sourceforge.net}.
327 Using the Network Connections control panel,
328 configure the TAP-Win32 network interface in the same way as you would do from the tinc-up script,
329 as explained in the rest of the documentation.
332 @c ==================================================================
338 Before you can configure or build tinc, you need to have the OpenSSL, zlib,
339 lzo, curses and readline libraries installed on your system. If you try to
340 configure tinc without having them installed, configure will give you an error
352 @c ==================================================================
357 For all cryptography-related functions, tinc uses the functions provided
358 by the OpenSSL library.
360 If this library is not installed, you wil get an error when configuring
361 tinc for build. Support for running tinc with other cryptographic libraries
362 installed @emph{may} be added in the future.
364 You can use your operating system's package manager to install this if
365 available. Make sure you install the development AND runtime versions
368 If you have to install OpenSSL manually, you can get the source code
369 from @url{http://www.openssl.org/}. Instructions on how to configure,
370 build and install this package are included within the package. Please
371 make sure you build development and runtime libraries (which is the
374 If you installed the OpenSSL libraries from source, it may be necessary
375 to let configure know where they are, by passing configure one of the
376 --with-openssl-* parameters.
379 --with-openssl=DIR OpenSSL library and headers prefix
380 --with-openssl-include=DIR OpenSSL headers directory
381 (Default is OPENSSL_DIR/include)
382 --with-openssl-lib=DIR OpenSSL library directory
383 (Default is OPENSSL_DIR/lib)
387 @subsubheading License
390 The complete source code of tinc is covered by the GNU GPL version 2.
391 Since the license under which OpenSSL is distributed is not directly
392 compatible with the terms of the GNU GPL
393 @uref{http://www.openssl.org/support/faq.html#LEGAL2}, we
394 include an exemption to the GPL (see also the file COPYING.README) to allow
395 everyone to create a statically or dynamically linked executable:
398 This program is released under the GPL with the additional exemption
399 that compiling, linking, and/or using OpenSSL is allowed. You may
400 provide binary packages linked to the OpenSSL libraries, provided that
401 all other requirements of the GPL are met.
404 Since the LZO library used by tinc is also covered by the GPL,
405 we also present the following exemption:
408 Hereby I grant a special exception to the tinc VPN project
409 (http://www.tinc-vpn.org/) to link the LZO library with the OpenSSL library
410 (http://www.openssl.org).
412 Markus F.X.J. Oberhumer
416 @c ==================================================================
421 For the optional compression of UDP packets, tinc uses the functions provided
424 If this library is not installed, you wil get an error when running the
425 configure script. You can either install the zlib library, or disable support
426 for zlib compression by using the "--disable-zlib" option when running the
427 configure script. Note that if you disable support for zlib, the resulting
428 binary will not work correctly on VPNs where zlib compression is used.
430 You can use your operating system's package manager to install this if
431 available. Make sure you install the development AND runtime versions
434 If you have to install zlib manually, you can get the source code
435 from @url{http://www.gzip.org/zlib/}. Instructions on how to configure,
436 build and install this package are included within the package. Please
437 make sure you build development and runtime libraries (which is the
441 @c ==================================================================
446 Another form of compression is offered using the LZO library.
448 If this library is not installed, you wil get an error when running the
449 configure script. You can either install the LZO library, or disable support
450 for LZO compression by using the "--disable-lzo" option when running the
451 configure script. Note that if you disable support for LZO, the resulting
452 binary will not work correctly on VPNs where LZO compression is used.
454 You can use your operating system's package manager to install this if
455 available. Make sure you install the development AND runtime versions
458 If you have to install lzo manually, you can get the source code
459 from @url{http://www.oberhumer.com/opensource/lzo/}. Instructions on how to configure,
460 build and install this package are included within the package. Please
461 make sure you build development and runtime libraries (which is the
465 @c ==================================================================
467 @subsection libcurses
470 For the "tinc top" command, tinc requires a curses library.
472 If this library is not installed, you wil get an error when running the
473 configure script. You can either install a suitable curses library, or disable
474 all functionality that depends on a curses library by using the
475 "--disable-curses" option when running the configure script.
477 There are several curses libraries. It is recommended that you install
478 "ncurses" (@url{http://invisible-island.net/ncurses/}),
479 however other curses libraries should also work.
480 In particular, "PDCurses" (@url{http://pdcurses.sourceforge.net/})
481 is recommended if you want to compile tinc for Windows.
483 You can use your operating system's package manager to install this if
484 available. Make sure you install the development AND runtime versions
488 @c ==================================================================
490 @subsection libreadline
493 For the "tinc" command's shell functionality, tinc uses the readline library.
495 If this library is not installed, you wil get an error when running the
496 configure script. You can either install a suitable readline library, or
497 disable all functionality that depends on a readline library by using the
498 "--disable-readline" option when running the configure script.
500 You can use your operating system's package manager to install this if
501 available. Make sure you install the development AND runtime versions
504 If you have to install libreadline manually, you can get the source code from
505 @url{http://www.gnu.org/software/readline/}. Instructions on how to configure,
506 build and install this package are included within the package. Please make
507 sure you build development and runtime libraries (which is the default).
519 @c ==================================================================
521 @chapter Installation
523 If you use Debian, you may want to install one of the
524 precompiled packages for your system. These packages are equipped with
525 system startup scripts and sample configurations.
527 If you cannot use one of the precompiled packages, or you want to compile tinc
528 for yourself, you can use the source. The source is distributed under
529 the GNU General Public License (GPL). Download the source from the
530 @uref{http://www.tinc-vpn.org/download/, download page}, which has
531 the checksums of these files listed; you may wish to check these with
532 md5sum before continuing.
534 Tinc comes in a convenient autoconf/automake package, which you can just
535 treat the same as any other package. Which is just untar it, type
536 `./configure' and then `make'.
537 More detailed instructions are in the file @file{INSTALL}, which is
538 included in the source distribution.
541 * Building and installing tinc::
546 @c ==================================================================
547 @node Building and installing tinc
548 @section Building and installing tinc
550 Detailed instructions on configuring the source, building tinc and installing tinc
551 can be found in the file called @file{INSTALL}.
553 @cindex binary package
554 If you happen to have a binary package for tinc for your distribution,
555 you can use the package management tools of that distribution to install tinc.
556 The documentation that comes along with your distribution will tell you how to do that.
559 * Darwin (MacOS/X) build environment::
560 * Cygwin (Windows) build environment::
561 * MinGW (Windows) build environment::
565 @c ==================================================================
566 @node Darwin (MacOS/X) build environment
567 @subsection Darwin (MacOS/X) build environment
569 In order to build tinc on Darwin, you need to install the MacOS/X Developer Tools
570 from @uref{http://developer.apple.com/tools/macosxtools.html} and
571 a recent version of Fink from @uref{http://www.finkproject.org/}.
573 After installation use fink to download and install the following packages:
574 autoconf25, automake, dlcompat, m4, openssl, zlib and lzo.
576 @c ==================================================================
577 @node Cygwin (Windows) build environment
578 @subsection Cygwin (Windows) build environment
580 If Cygwin hasn't already been installed, install it directly from
581 @uref{http://www.cygwin.com/}.
583 When tinc is compiled in a Cygwin environment, it can only be run in this environment,
584 but all programs, including those started outside the Cygwin environment, will be able to use the VPN.
585 It will also support all features.
587 @c ==================================================================
588 @node MinGW (Windows) build environment
589 @subsection MinGW (Windows) build environment
591 You will need to install the MinGW environment from @uref{http://www.mingw.org}.
593 When tinc is compiled using MinGW it runs natively under Windows,
594 it is not necessary to keep MinGW installed.
596 When detaching, tinc will install itself as a service,
597 which will be restarted automatically after reboots.
600 @c ==================================================================
602 @section System files
604 Before you can run tinc, you must make sure you have all the needed
605 files on your system.
613 @c ==================================================================
615 @subsection Device files
618 Most operating systems nowadays come with the necessary device files by default,
619 or they have a mechanism to create them on demand.
621 If you use Linux and do not have udev installed,
622 you may need to create the following device file if it does not exist:
625 mknod -m 600 /dev/net/tun c 10 200
629 @c ==================================================================
631 @subsection Other files
633 @subsubheading @file{/etc/networks}
635 You may add a line to @file{/etc/networks} so that your VPN will get a
636 symbolic name. For example:
642 @subsubheading @file{/etc/services}
645 You may add this line to @file{/etc/services}. The effect is that you
646 may supply a @samp{tinc} as a valid port number to some programs. The
647 number 655 is registered with the IANA.
652 # Ivo Timmermans <ivo@@tinc-vpn.org>
667 @c ==================================================================
669 @chapter Configuration
672 * Configuration introduction::
673 * Multiple networks::
674 * How connections work::
675 * Configuration files::
676 * Network interfaces::
677 * Example configuration::
680 @c ==================================================================
681 @node Configuration introduction
682 @section Configuration introduction
684 Before actually starting to configure tinc and editing files,
685 make sure you have read this entire section so you know what to expect.
686 Then, make it clear to yourself how you want to organize your VPN:
687 What are the nodes (computers running tinc)?
688 What IP addresses/subnets do they have?
689 What is the network mask of the entire VPN?
690 Do you need special firewall rules?
691 Do you have to set up masquerading or forwarding rules?
692 Do you want to run tinc in router mode or switch mode?
693 These questions can only be answered by yourself,
694 you will not find the answers in this documentation.
695 Make sure you have an adequate understanding of networks in general.
696 @cindex Network Administrators Guide
697 A good resource on networking is the
698 @uref{http://www.tldp.org/LDP/nag2/, Linux Network Administrators Guide}.
700 If you have everything clearly pictured in your mind,
701 proceed in the following order:
702 First, create the initial configuration files and public/private keypairs using the following command:
704 tinc -n @var{NETNAME} init @var{NAME}
706 Second, use @samp{tinc -n @var{NETNAME} add ...} to further configure tinc.
707 Finally, export your host configuration file using @samp{tinc -n @var{NETNAME} export} and send it to those
708 people or computers you want tinc to connect to.
709 They should send you their host configuration file back, which you can import using @samp{tinc -n @var{NETNAME} import}.
711 These steps are described in the subsections below.
714 @c ==================================================================
715 @node Multiple networks
716 @section Multiple networks
718 @cindex multiple networks
721 In order to allow you to run more than one tinc daemon on one computer,
722 for instance if your computer is part of more than one VPN,
723 you can assign a @var{netname} to your VPN.
724 It is not required if you only run one tinc daemon,
725 it doesn't even have to be the same on all the nodes of your VPN,
726 but it is recommended that you choose one anyway.
728 We will asume you use a netname throughout this document.
729 This means that you call tinc with the -n argument,
730 which will specify the netname.
732 The effect of this option is that tinc will set its configuration
733 root to @file{@value{sysconfdir}/tinc/@var{netname}/}, where @var{netname} is your argument to the -n option.
734 You will also notice that log messages it appears in syslog as coming from @file{tinc.@var{netname}},
735 and on Linux, unless specified otherwise, the name of the virtual network interface will be the same as the network name.
737 However, it is not strictly necessary that you call tinc with the -n
738 option. If you don not use it, the network name will just be empty, and
739 tinc will look for files in @file{@value{sysconfdir}/tinc/} instead of
740 @file{@value{sysconfdir}/tinc/@var{netname}/};
741 the configuration file will then be @file{@value{sysconfdir}/tinc/tinc.conf},
742 and the host configuration files are expected to be in @file{@value{sysconfdir}/tinc/hosts/}.
745 @c ==================================================================
746 @node How connections work
747 @section How connections work
749 When tinc starts up, it parses the command-line options and then
750 reads in the configuration file tinc.conf.
751 If it sees one or more `ConnectTo' values pointing to other tinc daemons in that file,
752 it will try to connect to those other daemons.
753 Whether this succeeds or not and whether `ConnectTo' is specified or not,
754 tinc will listen for incoming connection from other deamons.
755 If you did specify a `ConnectTo' value and the other side is not responding,
756 tinc will keep retrying.
757 This means that once started, tinc will stay running until you tell it to stop,
758 and failures to connect to other tinc daemons will not stop your tinc daemon
759 for trying again later.
760 This means you don't have to intervene if there are temporary network problems.
764 There is no real distinction between a server and a client in tinc.
765 If you wish, you can view a tinc daemon without a `ConnectTo' value as a server,
766 and one which does specify such a value as a client.
767 It does not matter if two tinc daemons have a `ConnectTo' value pointing to each other however.
769 Connections specified using `ConnectTo' are so-called meta-connections.
770 Tinc daemons exchange information about all other daemon they know about via these meta-connections.
771 After learning about all the daemons in the VPN,
772 tinc will create other connections as necessary in order to communicate with them.
773 For example, if there are three daemons named A, B and C, and A has @samp{ConnectTo = B} in its tinc.conf file,
774 and C has @samp{ConnectTo = B} in its tinc.conf file, then A will learn about C from B,
775 and will be able to exchange VPN packets with C without the need to have @samp{ConnectTo = C} in its tinc.conf file.
777 It could be that some daemons are located behind a Network Address Translation (NAT) device, or behind a firewall.
778 In the above scenario with three daemons, if A and C are behind a NAT,
779 B will automatically help A and C punch holes through their NAT,
780 in a way similar to the STUN protocol, so that A and C can still communicate with each other directly.
781 It is not always possible to do this however, and firewalls might also prevent direct communication.
782 In that case, VPN packets between A and C will be forwarded by B.
784 In effect, all nodes in the VPN will be able to talk to each other, as long as
785 their is a path of meta-connections between them, and whenever possible, two
786 nodes will communicate with each other directly.
789 @c ==================================================================
790 @node Configuration files
791 @section Configuration files
793 The actual configuration of the daemon is done in the file
794 @file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf} and at least one other file in the directory
795 @file{@value{sysconfdir}/tinc/@var{netname}/hosts/}.
797 An optionnal directory @file{@value{sysconfdir}/tinc/@var{netname}/conf.d} can be added from which
798 any .conf file will be read.
800 These file consists of comments (lines started with a #) or assignments
807 The variable names are case insensitive, and any spaces, tabs, newlines
808 and carriage returns are ignored. Note: it is not required that you put
809 in the `=' sign, but doing so improves readability. If you leave it
810 out, remember to replace it with at least one space character.
812 The server configuration is complemented with host specific configuration (see
813 the next section). Although all host configuration options for the local node
814 listed in this document can also be put in
815 @file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf}, it is recommended to
816 put host specific configuration options in the host configuration file, as this
817 makes it easy to exchange with other nodes.
819 You can edit the config file manually, but it is recommended that you use
820 the tinc command to change configuration variables for you.
822 In the following two subsections all valid variables are listed in alphabetical order.
823 The default value is given between parentheses,
824 other comments are between square brackets.
827 * Main configuration variables::
828 * Host configuration variables::
834 @c ==================================================================
835 @node Main configuration variables
836 @subsection Main configuration variables
839 @cindex AddressFamily
840 @item AddressFamily = <ipv4|ipv6|any> (any)
841 This option affects the address family of listening and outgoing sockets.
842 If any is selected, then depending on the operating system
843 both IPv4 and IPv6 or just IPv6 listening sockets will be created.
846 @item AutoConnect = <yes|no> (no) [experimental]
847 If set to yes, tinc will automatically set up meta connections to other nodes,
848 without requiring @var{ConnectTo} variables.
850 @cindex BindToAddress
851 @item BindToAddress = <@var{address}> [<@var{port}>]
852 This is the same as ListenAddress, however the address given with the BindToAddress option
853 will also be used for outgoing connections.
854 This is useful if your computer has more than one IPv4 or IPv6 address,
855 and you want tinc to only use a specific one for outgoing packets.
857 @cindex BindToInterface
858 @item BindToInterface = <@var{interface}> [experimental]
859 If you have more than one network interface in your computer, tinc will
860 by default listen on all of them for incoming connections. It is
861 possible to bind tinc to a single interface like eth0 or ppp0 with this
864 This option may not work on all platforms.
865 Also, on some platforms it will not actually bind to an interface,
866 but rather to the address that the interface has at the moment a socket is created.
869 @item Broadcast = <no | mst | direct> (mst) [experimental]
870 This option selects the way broadcast packets are sent to other daemons.
871 @emph{NOTE: all nodes in a VPN must use the same Broadcast mode, otherwise routing loops can form.}
875 Broadcast packets are never sent to other nodes.
878 Broadcast packets are sent and forwarded via the VPN's Minimum Spanning Tree.
879 This ensures broadcast packets reach all nodes.
882 Broadcast packets are sent directly to all nodes that can be reached directly.
883 Broadcast packets received from other nodes are never forwarded.
884 If the IndirectData option is also set, broadcast packets will only be sent to nodes which we have a meta connection to.
887 @cindex BroadcastSubnet
888 @item BroadcastSubnet = @var{address}[/@var{prefixlength}]
889 Declares a broadcast subnet.
890 Any packet with a destination address falling into such a subnet will be routed as a broadcast
891 (provided all nodes have it declared).
892 This is most useful to declare subnet broadcast addresses (e.g. 10.42.255.255),
893 otherwise tinc won't know what to do with them.
895 Note that global broadcast addresses (MAC ff:ff:ff:ff:ff:ff, IPv4 255.255.255.255),
896 as well as multicast space (IPv4 224.0.0.0/4, IPv6 ff00::/8)
897 are always considered broadcast addresses and don't need to be declared.
900 @item ConnectTo = <@var{name}>
901 Specifies which other tinc daemon to connect to on startup.
902 Multiple ConnectTo variables may be specified,
903 in which case outgoing connections to each specified tinc daemon are made.
904 The names should be known to this tinc daemon
905 (i.e., there should be a host configuration file for the name on the ConnectTo line).
907 If you don't specify a host with ConnectTo and don't enable AutoConnect,
908 tinc won't try to connect to other daemons at all,
909 and will instead just listen for incoming connections.
912 @item DecrementTTL = <yes | no> (no) [experimental]
913 When enabled, tinc will decrement the Time To Live field in IPv4 packets, or the Hop Limit field in IPv6 packets,
914 before forwarding a received packet to the virtual network device or to another node,
915 and will drop packets that have a TTL value of zero,
916 in which case it will send an ICMP Time Exceeded packet back.
918 Do not use this option if you use switch mode and want to use IPv6.
921 @item Device = <@var{device}> (@file{/dev/tap0}, @file{/dev/net/tun} or other depending on platform)
922 The virtual network device to use.
923 Tinc will automatically detect what kind of device it is.
924 Note that you can only use one device per daemon.
925 Under Windows, use @var{Interface} instead of @var{Device}.
926 Note that you can only use one device per daemon.
927 See also @ref{Device files}.
929 @cindex DeviceStandby
930 @item DeviceStandby = <yes | no> (no)
931 When disabled, tinc calls @file{tinc-up} on startup, and @file{tinc-down} on shutdown.
932 When enabled, tinc will only call @file{tinc-up} when at least one node is reachable,
933 and will call @file{tinc-down} as soon as no nodes are reachable.
934 On Windows, this also determines when the virtual network interface "cable" is "plugged".
937 @item DeviceType = <@var{type}> (platform dependent)
938 The type of the virtual network device.
939 Tinc will normally automatically select the right type of tun/tap interface, and this option should not be used.
940 However, this option can be used to select one of the special interface types, if support for them is compiled in.
945 Use a dummy interface.
946 No packets are ever read or written to a virtual network device.
947 Useful for testing, or when setting up a node that only forwards packets for other nodes.
951 Open a raw socket, and bind it to a pre-existing
952 @var{Interface} (eth0 by default).
953 All packets are read from this interface.
954 Packets received for the local node are written to the raw socket.
955 However, at least on Linux, the operating system does not process IP packets destined for the local host.
959 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}.
960 Packets are read from and written to this multicast socket.
961 This can be used to connect to UML, QEMU or KVM instances listening on the same multicast address.
962 Do NOT connect multiple tinc daemons to the same multicast address, this will very likely cause routing loops.
963 Also note that this can cause decrypted VPN packets to be sent out on a real network if misconfigured.
966 @item uml (not compiled in by default)
967 Create a UNIX socket with the filename specified by
968 @var{Device}, or @file{@value{localstatedir}/run/@var{netname}.umlsocket}
970 Tinc will wait for a User Mode Linux instance to connect to this socket.
973 @item vde (not compiled in by default)
974 Uses the libvdeplug library to connect to a Virtual Distributed Ethernet switch,
975 using the UNIX socket specified by
976 @var{Device}, or @file{@value{localstatedir}/run/vde.ctl}
980 Also, in case tinc does not seem to correctly interpret packets received from the virtual network device,
981 it can be used to change the way packets are interpreted:
984 @item tun (BSD and Linux)
986 Depending on the platform, this can either be with or without an address family header (see below).
989 @item tunnohead (BSD)
990 Set type to tun without an address family header.
991 Tinc will expect packets read from the virtual network device to start with an IP header.
992 On some platforms IPv6 packets cannot be read from or written to the device in this mode.
995 @item tunifhead (BSD)
996 Set type to tun with an address family header.
997 Tinc will expect packets read from the virtual network device
998 to start with a four byte header containing the address family,
999 followed by an IP header.
1000 This mode should support both IPv4 and IPv6 packets.
1002 @item tap (BSD and Linux)
1004 Tinc will expect packets read from the virtual network device
1005 to start with an Ethernet header.
1009 @item DirectOnly = <yes|no> (no) [experimental]
1010 When this option is enabled, packets that cannot be sent directly to the destination node,
1011 but which would have to be forwarded by an intermediate node, are dropped instead.
1012 When combined with the IndirectData option,
1013 packets for nodes for which we do not have a meta connection with are also dropped.
1015 @cindex Ed25519PrivateKeyFile
1016 @item Ed25519PrivateKeyFile = <@var{path}> (@file{@value{sysconfdir}/tinc/@var{netname}/ed25519_key.priv})
1017 The file in which the private Ed25519 key of this tinc daemon resides.
1018 This is only used if ExperimentalProtocol is enabled.
1020 @cindex ExperimentalProtocol
1021 @item ExperimentalProtocol = <yes|no> (yes)
1022 When this option is enabled, the SPTPS protocol will be used when connecting to nodes that also support it.
1023 Ephemeral ECDH will be used for key exchanges,
1024 and Ed25519 will be used instead of RSA for authentication.
1025 When enabled, an Ed25519 key must have been generated before with
1026 @samp{tinc generate-ed25519-keys}.
1029 @item Forwarding = <off|internal|kernel> (internal) [experimental]
1030 This option selects the way indirect packets are forwarded.
1034 Incoming packets that are not meant for the local node,
1035 but which should be forwarded to another node, are dropped.
1038 Incoming packets that are meant for another node are forwarded by tinc internally.
1040 This is the default mode, and unless you really know you need another forwarding mode, don't change it.
1043 Incoming packets are always sent to the TUN/TAP device, even if the packets are not for the local node.
1044 This is less efficient, but allows the kernel to apply its routing and firewall rules on them,
1045 and can also help debugging.
1049 @item Hostnames = <yes|no> (no)
1050 This option selects whether IP addresses (both real and on the VPN)
1051 should be resolved. Since DNS lookups are blocking, it might affect
1052 tinc's efficiency, even stopping the daemon for a few seconds everytime
1053 it does a lookup if your DNS server is not responding.
1055 This does not affect resolving hostnames to IP addresses from the
1056 configuration file, but whether hostnames should be resolved while logging.
1059 @item Interface = <@var{interface}>
1060 Defines the name of the interface corresponding to the virtual network device.
1061 Depending on the operating system and the type of device this may or may not actually set the name of the interface.
1062 Under Windows, this variable is used to select which network interface will be used.
1063 If you specified a Device, this variable is almost always already correctly set.
1065 @cindex ListenAddress
1066 @item ListenAddress = <@var{address}> [<@var{port}>]
1067 If your computer has more than one IPv4 or IPv6 address, tinc
1068 will by default listen on all of them for incoming connections.
1069 This option can be used to restrict which addresses tinc listens on.
1070 Multiple ListenAddress variables may be specified,
1071 in which case listening sockets for each specified address are made.
1073 If no @var{port} is specified, the socket will listen on the port specified by the Port option,
1074 or to port 655 if neither is given.
1075 To only listen on a specific port but not to a specific address, use "*" for the @var{address}.
1077 @cindex LocalDiscovery
1078 @item LocalDiscovery = <yes | no> (no)
1079 When enabled, tinc will try to detect peers that are on the same local network.
1080 This will allow direct communication using LAN addresses, even if both peers are behind a NAT
1081 and they only ConnectTo a third node outside the NAT,
1082 which normally would prevent the peers from learning each other's LAN address.
1084 Currently, local discovery is implemented by sending some packets to the local address of the node during UDP discovery.
1085 This will not work with old nodes that don't transmit their local address.
1087 @cindex LocalDiscoveryAddress
1088 @item LocalDiscoveryAddress <@var{address}>
1089 If this variable is specified, local discovery packets are sent to the given @var{address}.
1092 @item Mode = <router|switch|hub> (router)
1093 This option selects the way packets are routed to other daemons.
1099 variables in the host configuration files will be used to form a routing table.
1100 Only packets of routable protocols (IPv4 and IPv6) are supported in this mode.
1102 This is the default mode, and unless you really know you need another mode, don't change it.
1106 In this mode the MAC addresses of the packets on the VPN will be used to
1107 dynamically create a routing table just like an Ethernet switch does.
1108 Unicast, multicast and broadcast packets of every protocol that runs over Ethernet are supported in this mode
1109 at the cost of frequent broadcast ARP requests and routing table updates.
1111 This mode is primarily useful if you want to bridge Ethernet segments.
1115 This mode is almost the same as the switch mode, but instead
1116 every packet will be broadcast to the other daemons
1117 while no routing table is managed.
1121 @item KeyExpire = <@var{seconds}> (3600)
1122 This option controls the time the encryption keys used to encrypt the data
1123 are valid. It is common practice to change keys at regular intervals to
1124 make it even harder for crackers, even though it is thought to be nearly
1125 impossible to crack a single key.
1128 @item MACExpire = <@var{seconds}> (600)
1129 This option controls the amount of time MAC addresses are kept before they are removed.
1130 This only has effect when Mode is set to "switch".
1132 @cindex MaxConnectionBurst
1133 @item MaxConnectionBurst = <@var{count}> (100)
1134 This option controls how many connections tinc accepts in quick succession.
1135 If there are more connections than the given number in a short time interval,
1136 tinc will reduce the number of accepted connections to only one per second,
1137 until the burst has passed.
1140 @item Name = <@var{name}> [required]
1141 This is a symbolic name for this connection.
1142 The name should consist only of alfanumeric and underscore characters (a-z, A-Z, 0-9 and _), and is case sensitive.
1144 If Name starts with a $, then the contents of the environment variable that follows will be used.
1145 In that case, invalid characters will be converted to underscores.
1146 If Name is $HOST, but no such environment variable exist,
1147 the hostname will be read using the gethostname() system call.
1149 @cindex PingInterval
1150 @item PingInterval = <@var{seconds}> (60)
1151 The number of seconds of inactivity that tinc will wait before sending a
1152 probe to the other end.
1155 @item PingTimeout = <@var{seconds}> (5)
1156 The number of seconds to wait for a response to pings or to allow meta
1157 connections to block. If the other end doesn't respond within this time,
1158 the connection is terminated, and the others will be notified of this.
1160 @cindex PriorityInheritance
1161 @item PriorityInheritance = <yes|no> (no) [experimental]
1162 When this option is enabled the value of the TOS field of tunneled IPv4 packets
1163 will be inherited by the UDP packets that are sent out.
1166 @item PrivateKey = <@var{key}> [obsolete]
1167 This is the RSA private key for tinc. However, for safety reasons it is
1168 advised to store private keys of any kind in separate files. This prevents
1169 accidental eavesdropping if you are editting the configuration file.
1171 @cindex PrivateKeyFile
1172 @item PrivateKeyFile = <@var{path}> (@file{@value{sysconfdir}/tinc/@var{netname}/rsa_key.priv})
1173 This is the full path name of the RSA private key file that was
1174 generated by @samp{tinc generate-keys}. It must be a full path, not a
1177 @cindex ProcessPriority
1178 @item ProcessPriority = <low|normal|high>
1179 When this option is used the priority of the tincd process will be adjusted.
1180 Increasing the priority may help to reduce latency and packet loss on the VPN.
1183 @item Proxy = socks4 | socks5 | http | exec @var{...} [experimental]
1184 Use a proxy when making outgoing connections.
1185 The following proxy types are currently supported:
1189 @item socks4 <@var{address}> <@var{port}> [<@var{username}>]
1190 Connects to the proxy using the SOCKS version 4 protocol.
1191 Optionally, a @var{username} can be supplied which will be passed on to the proxy server.
1194 @item socks5 <@var{address}> <@var{port}> [<@var{username}> <@var{password}>]
1195 Connect to the proxy using the SOCKS version 5 protocol.
1196 If a @var{username} and @var{password} are given, basic username/password authentication will be used,
1197 otherwise no authentication will be used.
1200 @item http <@var{address}> <@var{port}>
1201 Connects to the proxy and sends a HTTP CONNECT request.
1204 @item exec <@var{command}>
1205 Executes the given command which should set up the outgoing connection.
1206 The environment variables @env{NAME}, @env{NODE}, @env{REMOTEADDRES} and @env{REMOTEPORT} are available.
1209 @cindex ReplayWindow
1210 @item ReplayWindow = <bytes> (16)
1211 This is the size of the replay tracking window for each remote node, in bytes.
1212 The window is a bitfield which tracks 1 packet per bit, so for example
1213 the default setting of 16 will track up to 128 packets in the window. In high
1214 bandwidth scenarios, setting this to a higher value can reduce packet loss from
1215 the interaction of replay tracking with underlying real packet loss and/or
1216 reordering. Setting this to zero will disable replay tracking completely and
1217 pass all traffic, but leaves tinc vulnerable to replay-based attacks on your
1220 @cindex StrictSubnets
1221 @item StrictSubnets = <yes|no> (no) [experimental]
1222 When this option is enabled tinc will only use Subnet statements which are
1223 present in the host config files in the local
1224 @file{@value{sysconfdir}/tinc/@var{netname}/hosts/} directory.
1225 Subnets learned via connections to other nodes and which are not
1226 present in the local host config files are ignored.
1228 @cindex TunnelServer
1229 @item TunnelServer = <yes|no> (no) [experimental]
1230 When this option is enabled tinc will no longer forward information between other tinc daemons,
1231 and will only allow connections with nodes for which host config files are present in the local
1232 @file{@value{sysconfdir}/tinc/@var{netname}/hosts/} directory.
1233 Setting this options also implicitly sets StrictSubnets.
1236 @item UDPDiscovery = <yes|no> (yes)
1237 When this option is enabled tinc will try to establish UDP connectivity to nodes,
1238 using TCP while it determines if a node is reachable over UDP. If it is disabled,
1239 tinc always assumes a node is reachable over UDP.
1240 Note that tinc will never use UDP with nodes that have TCPOnly enabled.
1242 @cindex UDPDiscoveryKeepaliveInterval
1243 @item UDPDiscoveryKeepaliveInterval = <seconds> (9)
1244 The minimum amount of time between sending UDP ping datagrams to check UDP connectivity once it has been established.
1245 Note that these pings are large, since they are used to verify link MTU as well.
1247 @cindex UDPDiscoveryInterval
1248 @item UDPDiscoveryInterval = <seconds> (2)
1249 The minimum amount of time between sending UDP ping datagrams to try to establish UDP connectivity.
1251 @cindex UDPDiscoveryTimeout
1252 @item UDPDiscoveryTimeout = <seconds> (30)
1253 If tinc doesn't receive any UDP ping replies over the specified interval,
1254 it will assume UDP communication is broken and will fall back to TCP.
1256 @cindex UDPInfoInterval
1257 @item UDPInfoInterval = <seconds> (5)
1258 The minimum amount of time between sending periodic updates about UDP addresses, which are mostly useful for UDP hole punching.
1261 @item UDPRcvBuf = <bytes> (OS default)
1262 Sets the socket receive buffer size for the UDP socket, in bytes.
1263 If unset, the default buffer size will be used by the operating system.
1266 @item UDPSndBuf = <bytes> Pq OS default
1267 Sets the socket send buffer size for the UDP socket, in bytes.
1268 If unset, the default buffer size will be used by the operating system.
1273 @c ==================================================================
1274 @node Host configuration variables
1275 @subsection Host configuration variables
1279 @item Address = <@var{IP address}|@var{hostname}> [<port>] [recommended]
1280 This variable is only required if you want to connect to this host. It
1281 must resolve to the external IP address where the host can be reached,
1282 not the one that is internal to the VPN.
1283 If no port is specified, the default Port is used.
1284 Multiple Address variables can be specified, in which case each address will be
1285 tried until a working connection has been established.
1288 @item Cipher = <@var{cipher}> (blowfish)
1289 The symmetric cipher algorithm used to encrypt UDP packets using the legacy protocol.
1290 Any cipher supported by OpenSSL is recognized.
1291 Furthermore, specifying "none" will turn off packet encryption.
1292 It is best to use only those ciphers which support CBC mode.
1293 This option has no effect for connections using the SPTPS protocol, which always use AES-256-CTR.
1296 @item ClampMSS = <yes|no> (yes)
1297 This option specifies whether tinc should clamp the maximum segment size (MSS)
1298 of TCP packets to the path MTU. This helps in situations where ICMP
1299 Fragmentation Needed or Packet too Big messages are dropped by firewalls.
1302 @item Compression = <@var{level}> (0)
1303 This option sets the level of compression used for UDP packets.
1304 Possible values are 0 (off), 1 (fast zlib) and any integer up to 9 (best zlib),
1305 10 (fast lzo) and 11 (best lzo).
1308 @item Digest = <@var{digest}> (sha1)
1309 The digest algorithm used to authenticate UDP packets using the legacy protocol.
1310 Any digest supported by OpenSSL is recognized.
1311 Furthermore, specifying "none" will turn off packet authentication.
1312 This option has no effect for connections using the SPTPS protocol, which always use HMAC-SHA-256.
1314 @cindex IndirectData
1315 @item IndirectData = <yes|no> (no)
1316 When set to yes, other nodes which do not already have a meta connection to you
1317 will not try to establish direct communication with you.
1318 It is best to leave this option out or set it to no.
1321 @item MACLength = <@var{bytes}> (4)
1322 The length of the message authentication code used to authenticate UDP packets using the legacy protocol.
1323 Can be anything from 0
1324 up to the length of the digest produced by the digest algorithm.
1325 This option has no effect for connections using the SPTPS protocol, which never truncate MACs.
1328 @item PMTU = <@var{mtu}> (1514)
1329 This option controls the initial path MTU to this node.
1331 @cindex PMTUDiscovery
1332 @item PMTUDiscovery = <yes|no> (yes)
1333 When this option is enabled, tinc will try to discover the path MTU to this node.
1334 After the path MTU has been discovered, it will be enforced on the VPN.
1336 @cindex MTUInfoInterval
1337 @item MTUInfoInterval = <seconds> (5)
1338 The minimum amount of time between sending periodic updates about relay path MTU. Useful for quickly determining MTU to indirect nodes.
1341 @item Port = <@var{port}> (655)
1342 This is the port this tinc daemon listens on.
1343 You can use decimal portnumbers or symbolic names (as listed in @file{/etc/services}).
1346 @item PublicKey = <@var{key}> [obsolete]
1347 This is the RSA public key for this host.
1349 @cindex PublicKeyFile
1350 @item PublicKeyFile = <@var{path}> [obsolete]
1351 This is the full path name of the RSA public key file that was generated
1352 by @samp{tinc generate-keys}. It must be a full path, not a relative
1356 From version 1.0pre4 on tinc will store the public key directly into the
1357 host configuration file in PEM format, the above two options then are not
1358 necessary. Either the PEM format is used, or exactly
1359 @strong{one of the above two options} must be specified
1360 in each host configuration file, if you want to be able to establish a
1361 connection with that host.
1364 @item Subnet = <@var{address}[/@var{prefixlength}[#@var{weight}]]>
1365 The subnet which this tinc daemon will serve.
1366 Tinc tries to look up which other daemon it should send a packet to by searching the appropiate subnet.
1367 If the packet matches a subnet,
1368 it will be sent to the daemon who has this subnet in his host configuration file.
1369 Multiple subnet lines can be specified for each daemon.
1371 Subnets can either be single MAC, IPv4 or IPv6 addresses,
1372 in which case a subnet consisting of only that single address is assumed,
1373 or they can be a IPv4 or IPv6 network address with a prefixlength.
1374 For example, IPv4 subnets must be in a form like 192.168.1.0/24,
1375 where 192.168.1.0 is the network address and 24 is the number of bits set in the netmask.
1376 Note that subnets like 192.168.1.1/24 are invalid!
1377 Read a networking HOWTO/FAQ/guide if you don't understand this.
1378 IPv6 subnets are notated like fec0:0:0:1::/64.
1379 MAC addresses are notated like 0:1a:2b:3c:4d:5e.
1381 @cindex CIDR notation
1382 Prefixlength is the number of bits set to 1 in the netmask part; for
1383 example: netmask 255.255.255.0 would become /24, 255.255.252.0 becomes
1384 /22. This conforms to standard CIDR notation as described in
1385 @uref{http://www.ietf.org/rfc/rfc1519.txt, RFC1519}
1387 A Subnet can be given a weight to indicate its priority over identical Subnets
1388 owned by different nodes. The default weight is 10. Lower values indicate
1389 higher priority. Packets will be sent to the node with the highest priority,
1390 unless that node is not reachable, in which case the node with the next highest
1391 priority will be tried, and so on.
1394 @item TCPonly = <yes|no> (no)
1395 If this variable is set to yes, then the packets are tunnelled over a
1396 TCP connection instead of a UDP connection. This is especially useful
1397 for those who want to run a tinc daemon from behind a masquerading
1398 firewall, or if UDP packet routing is disabled somehow.
1399 Setting this options also implicitly sets IndirectData.
1402 @item Weight = <weight>
1403 If this variable is set, it overrides the weight given to connections made with
1404 another host. A higher weight means a lower priority is given to this
1405 connection when broadcasting or forwarding packets.
1409 @c ==================================================================
1414 Apart from reading the server and host configuration files,
1415 tinc can also run scripts at certain moments.
1416 Under Windows (not Cygwin), the scripts should have the extension @file{.bat} or @file{.cmd}.
1420 @item @value{sysconfdir}/tinc/@var{netname}/tinc-up
1421 This is the most important script.
1422 If it is present it will be executed right after the tinc daemon has been
1423 started and has connected to the virtual network device.
1424 It should be used to set up the corresponding network interface,
1425 but can also be used to start other things.
1426 Under Windows you can use the Network Connections control panel instead of creating this script.
1429 @item @value{sysconfdir}/tinc/@var{netname}/tinc-down
1430 This script is started right before the tinc daemon quits.
1432 @item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-up
1433 This script is started when the tinc daemon with name @var{host} becomes reachable.
1435 @item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-down
1436 This script is started when the tinc daemon with name @var{host} becomes unreachable.
1438 @item @value{sysconfdir}/tinc/@var{netname}/host-up
1439 This script is started when any host becomes reachable.
1441 @item @value{sysconfdir}/tinc/@var{netname}/host-down
1442 This script is started when any host becomes unreachable.
1444 @item @value{sysconfdir}/tinc/@var{netname}/subnet-up
1445 This script is started when a Subnet becomes reachable.
1446 The Subnet and the node it belongs to are passed in environment variables.
1448 @item @value{sysconfdir}/tinc/@var{netname}/subnet-down
1449 This script is started when a Subnet becomes unreachable.
1451 @item @value{sysconfdir}/tinc/@var{netname}/invitation-created
1452 This script is started when a new invitation has been created.
1454 @item @value{sysconfdir}/tinc/@var{netname}/invitation-accepted
1455 This script is started when an invitation has been used.
1459 @cindex environment variables
1460 The scripts are started without command line arguments,
1461 but can make use of certain environment variables.
1462 Under UNIX like operating systems the names of environment variables must be preceded by a $ in scripts.
1463 Under Windows, in @file{.bat} or @file{.cmd} files, they have to be put between % signs.
1468 If a netname was specified, this environment variable contains it.
1472 Contains the name of this tinc daemon.
1476 Contains the name of the virtual network device that tinc uses.
1480 Contains the name of the virtual network interface that tinc uses.
1481 This should be used for commands like ifconfig.
1485 When a host becomes (un)reachable, this is set to its name.
1486 If a subnet becomes (un)reachable, this is set to the owner of that subnet.
1488 @cindex REMOTEADDRESS
1490 When a host becomes (un)reachable, this is set to its real address.
1494 When a host becomes (un)reachable,
1495 this is set to the port number it uses for communication with other tinc daemons.
1499 When a subnet becomes (un)reachable, this is set to the subnet.
1503 When a subnet becomes (un)reachable, this is set to the subnet weight.
1505 @cindex INVITATION_FILE
1506 @item INVITATION_FILE
1507 When the @file{invitation-created} script is called,
1508 this is set to the file where the invitation details will be stored.
1510 @cindex INVITATION_URL
1511 @item INVITATION_URL
1512 When the @file{invitation-created} script is called,
1513 this is set to the invitation URL that has been created.
1516 Do not forget that under UNIX operating systems,
1517 you have to make the scripts executable, using the command @samp{chmod a+x script}.
1520 @c ==================================================================
1521 @node How to configure
1522 @subsection How to configure
1524 @subsubheading Step 1. Creating initial configuration files.
1526 The initial directory structure, configuration files and public/private keypairs are created using the following command:
1529 tinc -n @var{netname} init @var{name}
1532 (You will need to run this as root, or use "sudo".)
1533 This will create the configuration directory @file{@value{sysconfdir}/tinc/@var{netname}.},
1534 and inside it will create another directory named @file{hosts/}.
1535 In the configuration directory, it will create the file @file{tinc.conf} with the following contents:
1541 It will also create private RSA and Ed25519 keys, which will be stored in the files @file{rsa_key.priv} and @file{ed25519_key.priv}.
1542 It will also create a host configuration file @file{hosts/@var{name}},
1543 which will contain the corresponding public RSA and Ed25519 keys.
1545 Finally, on UNIX operating systems, it will create an executable script @file{tinc-up},
1546 which will initially not do anything except warning that you should edit it.
1548 @subsubheading Step 2. Modifying the initial configuration.
1550 Unless you want to use tinc in switch mode,
1551 you should now configure which range of addresses you will use on the VPN.
1552 Let's assume you will be part of a VPN which uses the address range 192.168.0.0/16,
1553 and you yourself have a smaller portion of that range: 192.168.2.0/24.
1554 Then you should run the following command:
1557 tinc -n @var{netname} add subnet 192.168.2.0/24
1560 This will add a Subnet statement to your host configuration file.
1561 Try opening the file @file{@value{sysconfdir}/tinc/@var{netname}/hosts/@var{name}} in an editor.
1562 You should now see a file containing the public RSA and Ed25519 keys (which looks like a bunch of random characters),
1563 and the following line at the bottom:
1566 Subnet = 192.168.2.0/24
1569 If you will use more than one address range, you can add more Subnets.
1570 For example, if you also use the IPv6 subnet fec0:0:0:2::/64, you can add it as well:
1573 tinc -n @var{netname} add subnet fec0:0:0:2::/24
1576 This will add another line to the file @file{hosts/@var{name}}.
1577 If you make a mistake, you can undo it by simply using @samp{del} instead of @samp{add}.
1579 If you want other tinc daemons to create meta-connections to your daemon,
1580 you should add your public IP address or hostname to your host configuration file.
1581 For example, if your hostname is foo.example.org, run:
1584 tinc -n @var{netname} add address foo.example.org
1587 If you already know to which daemons your daemon should make meta-connections,
1588 you should configure that now as well.
1589 Suppose you want to connect to a daemon named "bar", run:
1592 tinc -n @var{netname} add connectto bar
1595 Note that you specify the Name of the other daemon here, not an IP address or hostname!
1596 When you start tinc, and it tries to make a connection to "bar",
1597 it will look for a host configuration file named @file{hosts/bar},
1598 and will read Address statements and public keys from that file.
1600 @subsubheading Step 2. Exchanging configuration files.
1602 If your daemon has a ConnectTo = bar statement in its @file{tinc.conf} file,
1603 or if bar has a ConnectTo your daemon, then you both need each other's host configuration files.
1604 You should send @file{hosts/@var{name}} to bar, and bar should send you his file which you should move to @file{hosts/bar}.
1605 If you are on a UNIX platform, you can easily send an email containing the necessary information using the following command
1606 (assuming the owner of bar has the email address bar@@example.org):
1609 tinc -n @var{netname} export | mail -s "My config file" bar@@example.org
1612 If the owner of bar does the same to send his host configuration file to you,
1613 you can probably pipe his email through the following command,
1614 or you can just start this command in a terminal and copy&paste the email:
1617 tinc -n @var{netname} import
1620 If you are the owner of bar yourself, and you have SSH access to that computer,
1621 you can also swap the host configuration files using the following command:
1624 tinc -n @var{netname} export \
1625 | ssh bar.example.org tinc -n @var{netname} exchange \
1626 | tinc -n @var{netname} import
1629 You should repeat this for all nodes you ConnectTo, or which ConnectTo you.
1630 However, remember that you do not need to ConnectTo all nodes in the VPN;
1631 it is only necessary to create one or a few meta-connections,
1632 after the connections are made tinc will learn about all the other nodes in the VPN,
1633 and will automatically make other connections as necessary.
1636 @c ==================================================================
1637 @node Network interfaces
1638 @section Network interfaces
1640 Before tinc can start transmitting data over the tunnel, it must
1641 set up the virtual network interface.
1643 First, decide which IP addresses you want to have associated with these
1644 devices, and what network mask they must have.
1646 Tinc will open a virtual network device (@file{/dev/tun}, @file{/dev/tap0} or similar),
1647 which will also create a network interface called something like @samp{tun0}, @samp{tap0}.
1648 If you are using the Linux tun/tap driver, the network interface will by default have the same name as the @var{netname}.
1649 Under Windows you can change the name of the network interface from the Network Connections control panel.
1652 You can configure the network interface by putting ordinary ifconfig, route, and other commands
1653 to a script named @file{@value{sysconfdir}/tinc/@var{netname}/tinc-up}.
1654 When tinc starts, this script will be executed. When tinc exits, it will execute the script named
1655 @file{@value{sysconfdir}/tinc/@var{netname}/tinc-down}, but normally you don't need to create that script.
1656 You can manually open the script in an editor, or use the following command:
1659 tinc -n @var{netname} edit tinc-up
1662 An example @file{tinc-up} script, that would be appropriate for the scenario in the previous section, is:
1666 ifconfig $INTERFACE 192.168.2.1 netmask 255.255.0.0
1667 ip addr add fec0:0:0:2::/48 dev $INTERFACE
1670 The first command gives the interface an IPv4 address and a netmask.
1671 The kernel will also automatically add an IPv4 route to this interface, so normally you don't need
1672 to add route commands to the @file{tinc-up} script.
1673 The kernel will also bring the interface up after this command.
1675 The netmask is the mask of the @emph{entire} VPN network, not just your
1677 The second command gives the interface an IPv6 address and netmask,
1678 which will also automatically add an IPv6 route.
1679 If you only want to use "ip addr" commands on Linux, don't forget that it doesn't bring the interface up, unlike ifconfig,
1680 so you need to add @samp{ip link set $INTERFACE up} in that case.
1682 The exact syntax of the ifconfig and route commands differs from platform to platform.
1683 You can look up the commands for setting addresses and adding routes in @ref{Platform specific information},
1684 but it is best to consult the manpages of those utilities on your platform.
1687 @c ==================================================================
1688 @node Example configuration
1689 @section Example configuration
1693 Imagine the following situation. Branch A of our example `company' wants to connect
1694 three branch offices in B, C and D using the Internet. All four offices
1695 have a 24/7 connection to the Internet.
1697 A is going to serve as the center of the network. B and C will connect
1698 to A, and D will connect to C. Each office will be assigned their own IP
1702 A: net 10.1.0.0 mask 255.255.0.0 gateway 10.1.54.1 internet IP 1.2.3.4
1703 B: net 10.2.0.0 mask 255.255.0.0 gateway 10.2.1.12 internet IP 2.3.4.5
1704 C: net 10.3.0.0 mask 255.255.0.0 gateway 10.3.69.254 internet IP 3.4.5.6
1705 D: net 10.4.0.0 mask 255.255.0.0 gateway 10.4.3.32 internet IP 4.5.6.7
1708 Here, ``gateway'' is the VPN IP address of the machine that is running the
1709 tincd, and ``internet IP'' is the IP address of the firewall, which does not
1710 need to run tincd, but it must do a port forwarding of TCP and UDP on port
1711 655 (unless otherwise configured).
1713 In this example, it is assumed that eth0 is the interface that points to
1714 the inner (physical) LAN of the office, although this could also be the
1715 same as the interface that leads to the Internet. The configuration of
1716 the real interface is also shown as a comment, to give you an idea of
1717 how these example host is set up. All branches use the netname `company'
1718 for this particular VPN.
1720 Each branch is set up using the @samp{tinc init} and @samp{tinc config} commands,
1721 here we just show the end results:
1723 @subsubheading For Branch A
1725 @emph{BranchA} would be configured like this:
1727 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1732 # Real interface of internal network:
1733 # ifconfig eth0 10.1.54.1 netmask 255.255.0.0
1735 ifconfig $INTERFACE 10.1.54.1 netmask 255.0.0.0
1738 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1744 On all hosts, @file{@value{sysconfdir}/tinc/company/hosts/BranchA} contains:
1747 Subnet = 10.1.0.0/16
1750 -----BEGIN RSA PUBLIC KEY-----
1752 -----END RSA PUBLIC KEY-----
1755 Note that the IP addresses of eth0 and the VPN interface are the same.
1756 This is quite possible, if you make sure that the netmasks of the interfaces are different.
1757 It is in fact recommended to give both real internal network interfaces and VPN interfaces the same IP address,
1758 since that will make things a lot easier to remember and set up.
1761 @subsubheading For Branch B
1763 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1768 # Real interface of internal network:
1769 # ifconfig eth0 10.2.43.8 netmask 255.255.0.0
1771 ifconfig $INTERFACE 10.2.1.12 netmask 255.0.0.0
1774 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1781 Note here that the internal address (on eth0) doesn't have to be the
1782 same as on the VPN interface. Also, ConnectTo is given so that this node will
1783 always try to connect to BranchA.
1785 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchB}:
1788 Subnet = 10.2.0.0/16
1791 -----BEGIN RSA PUBLIC KEY-----
1793 -----END RSA PUBLIC KEY-----
1797 @subsubheading For Branch C
1799 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1804 # Real interface of internal network:
1805 # ifconfig eth0 10.3.69.254 netmask 255.255.0.0
1807 ifconfig $INTERFACE 10.3.69.254 netmask 255.0.0.0
1810 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1817 C already has another daemon that runs on port 655, so they have to
1818 reserve another port for tinc. It knows the portnumber it has to listen on
1819 from it's own host configuration file.
1821 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchC}:
1825 Subnet = 10.3.0.0/16
1828 -----BEGIN RSA PUBLIC KEY-----
1830 -----END RSA PUBLIC KEY-----
1834 @subsubheading For Branch D
1836 In @file{@value{sysconfdir}/tinc/company/tinc-up}:
1841 # Real interface of internal network:
1842 # ifconfig eth0 10.4.3.32 netmask 255.255.0.0
1844 ifconfig $INTERFACE 10.4.3.32 netmask 255.0.0.0
1847 and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
1854 D will be connecting to C, which has a tincd running for this network on
1855 port 2000. It knows the port number from the host configuration file.
1857 On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchD}:
1860 Subnet = 10.4.0.0/16
1863 -----BEGIN RSA PUBLIC KEY-----
1865 -----END RSA PUBLIC KEY-----
1868 @subsubheading Key files
1870 A, B, C and D all have their own public/private keypairs:
1872 The private RSA key is stored in @file{@value{sysconfdir}/tinc/company/rsa_key.priv},
1873 the private Ed25519 key is stored in @file{@value{sysconfdir}/tinc/company/ed25519_key.priv},
1874 and the public RSA and Ed25519 keys are put into the host configuration file in the @file{@value{sysconfdir}/tinc/company/hosts/} directory.
1876 @subsubheading Starting
1878 After each branch has finished configuration and they have distributed
1879 the host configuration files amongst them, they can start their tinc daemons.
1880 They don't necessarily have to wait for the other branches to have started
1881 their daemons, tinc will try connecting until they are available.
1884 @c ==================================================================
1886 @chapter Running tinc
1888 If everything else is done, you can start tinc by typing the following command:
1891 tinc -n @var{netname} start
1895 Tinc will detach from the terminal and continue to run in the background like a good daemon.
1896 If there are any problems however you can try to increase the debug level
1897 and look in the syslog to find out what the problems are.
1903 * Solving problems::
1905 * Sending bug reports::
1909 @c ==================================================================
1910 @node Runtime options
1911 @section Runtime options
1913 Besides the settings in the configuration file, tinc also accepts some
1914 command line options.
1916 @cindex command line
1917 @cindex runtime options
1921 @item -c, --config=@var{path}
1922 Read configuration options from the directory @var{path}. The default is
1923 @file{@value{sysconfdir}/tinc/@var{netname}/}.
1925 @item -D, --no-detach
1926 Don't fork and detach.
1927 This will also disable the automatic restart mechanism for fatal errors.
1930 @item -d, --debug=@var{level}
1931 Set debug level to @var{level}. The higher the debug level, the more gets
1932 logged. Everything goes via syslog.
1934 @item -n, --net=@var{netname}
1935 Use configuration for net @var{netname}.
1936 This will let tinc read all configuration files from
1937 @file{@value{sysconfdir}/tinc/@var{netname}/}.
1938 Specifying . for @var{netname} is the same as not specifying any @var{netname}.
1939 @xref{Multiple networks}.
1941 @item --pidfile=@var{filename}
1942 Store a cookie in @var{filename} which allows tinc to authenticate.
1943 If unspecified, the default is
1944 @file{@value{localstatedir}/run/tinc.@var{netname}.pid}.
1946 @item -o, --option=[@var{HOST}.]@var{KEY}=@var{VALUE}
1947 Without specifying a @var{HOST}, this will set server configuration variable @var{KEY} to @var{VALUE}.
1948 If specified as @var{HOST}.@var{KEY}=@var{VALUE},
1949 this will set the host configuration variable @var{KEY} of the host named @var{HOST} to @var{VALUE}.
1950 This option can be used more than once to specify multiple configuration variables.
1953 Lock tinc into main memory.
1954 This will prevent sensitive data like shared private keys to be written to the system swap files/partitions.
1956 This option is not supported on all platforms.
1958 @item --logfile[=@var{file}]
1959 Write log entries to a file instead of to the system logging facility.
1960 If @var{file} is omitted, the default is @file{@value{localstatedir}/log/tinc.@var{netname}.log}.
1962 @item --bypass-security
1963 Disables encryption and authentication.
1964 Only useful for debugging.
1967 Change process root directory to the directory where the config file is
1968 located (@file{@value{sysconfdir}/tinc/@var{netname}/} as determined by
1969 -n/--net option or as given by -c/--config option), for added security.
1970 The chroot is performed after all the initialization is done, after
1971 writing pid files and opening network sockets.
1973 Note that this option alone does not do any good without -U/--user, below.
1975 Note also that tinc can't run scripts anymore (such as tinc-down or host-up),
1976 unless it's setup to be runnable inside chroot environment.
1978 This option is not supported on all platforms.
1979 @item -U, --user=@var{user}
1980 Switch to the given @var{user} after initialization, at the same time as
1981 chroot is performed (see --chroot above). With this option tinc drops
1982 privileges, for added security.
1984 This option is not supported on all platforms.
1987 Display a short reminder of these runtime options and terminate.
1990 Output version information and exit.
1994 @c ==================================================================
1999 You can also send the following signals to a running tincd process:
2005 Forces tinc to try to connect to all uplinks immediately.
2006 Usually tinc attempts to do this itself,
2007 but increases the time it waits between the attempts each time it failed,
2008 and if tinc didn't succeed to connect to an uplink the first time after it started,
2009 it defaults to the maximum time of 15 minutes.
2012 Partially rereads configuration files.
2013 Connections to hosts whose host config file are removed are closed.
2014 New outgoing connections specified in @file{tinc.conf} will be made.
2015 If the --logfile option is used, this will also close and reopen the log file,
2016 useful when log rotation is used.
2020 @c ==================================================================
2022 @section Debug levels
2024 @cindex debug levels
2025 The tinc daemon can send a lot of messages to the syslog.
2026 The higher the debug level, the more messages it will log.
2027 Each level inherits all messages of the previous level:
2033 This will log a message indicating tinc has started along with a version number.
2034 It will also log any serious error.
2037 This will log all connections that are made with other tinc daemons.
2040 This will log status and error messages from scripts and other tinc daemons.
2043 This will log all requests that are exchanged with other tinc daemons. These include
2044 authentication, key exchange and connection list updates.
2047 This will log a copy of everything received on the meta socket.
2050 This will log all network traffic over the virtual private network.
2054 @c ==================================================================
2055 @node Solving problems
2056 @section Solving problems
2058 If tinc starts without problems, but if the VPN doesn't work, you will have to find the cause of the problem.
2059 The first thing to do is to start tinc with a high debug level in the foreground,
2060 so you can directly see everything tinc logs:
2063 tincd -n @var{netname} -d5 -D
2066 If tinc does not log any error messages, then you might want to check the following things:
2069 @item @file{tinc-up} script
2070 Does this script contain the right commands?
2071 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.
2074 Does the Subnet (or Subnets) in the host configuration file of this host match the portion of the VPN that belongs to this host?
2076 @item Firewalls and NATs
2077 Do you have a firewall or a NAT device (a masquerading firewall or perhaps an ADSL router that performs masquerading)?
2078 If so, check that it allows TCP and UDP traffic on port 655.
2079 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.
2080 You can add @samp{TCPOnly = yes} to your host config file to force tinc to only use a single TCP connection,
2081 this works through most firewalls and NATs.
2086 @c ==================================================================
2087 @node Error messages
2088 @section Error messages
2090 What follows is a list of the most common error messages you might find in the logs.
2091 Some of them will only be visible if the debug level is high enough.
2094 @item Could not open /dev/tap0: No such device
2097 @item You forgot to `modprobe netlink_dev' or `modprobe ethertap'.
2098 @item You forgot to compile `Netlink device emulation' in the kernel.
2101 @item Can't write to /dev/net/tun: No such device
2104 @item You forgot to `modprobe tun'.
2105 @item You forgot to compile `Universal TUN/TAP driver' in the kernel.
2106 @item The tun device is located somewhere else in @file{/dev/}.
2109 @item Network address and prefix length do not match!
2112 @item The Subnet field must contain a @emph{network} address, trailing bits should be 0.
2113 @item If you only want to use one IP address, set the netmask to /32.
2116 @item Error reading RSA key file `rsa_key.priv': No such file or directory
2119 @item You forgot to create a public/private keypair.
2120 @item Specify the complete pathname to the private key file with the @samp{PrivateKeyFile} option.
2123 @item Warning: insecure file permissions for RSA private key file `rsa_key.priv'!
2126 @item The private key file is readable by users other than root.
2127 Use chmod to correct the file permissions.
2130 @item Creating metasocket failed: Address family not supported
2133 @item By default tinc tries to create both IPv4 and IPv6 sockets.
2134 On some platforms this might not be implemented.
2135 If the logs show @samp{Ready} later on, then at least one metasocket was created,
2136 and you can ignore this message.
2137 You can add @samp{AddressFamily = ipv4} to @file{tinc.conf} to prevent this from happening.
2140 @item Cannot route packet: unknown IPv4 destination 1.2.3.4
2143 @item You try to send traffic to a host on the VPN for which no Subnet is known.
2144 @item If it is a broadcast address (ending in .255), it probably is a samba server or a Windows host sending broadcast packets.
2148 @item Cannot route packet: ARP request for unknown address 1.2.3.4
2151 @item You try to send traffic to a host on the VPN for which no Subnet is known.
2154 @item Packet with destination 1.2.3.4 is looping back to us!
2157 @item Something is not configured right. Packets are being sent out to the
2158 virtual network device, but according to the Subnet directives in your host configuration
2159 file, those packets should go to your own host. Most common mistake is that
2160 you have a Subnet line in your host configuration file with a prefix length which is
2161 just as large as the prefix of the virtual network interface. The latter should in almost all
2162 cases be larger. Rethink your configuration.
2163 Note that you will only see this message if you specified a debug
2164 level of 5 or higher!
2165 @item Chances are that a @samp{Subnet = ...} line in the host configuration file of this tinc daemon is wrong.
2166 Change it to a subnet that is accepted locally by another interface,
2167 or if that is not the case, try changing the prefix length into /32.
2170 @item Node foo (1.2.3.4) is not reachable
2173 @item Node foo does not have a connection anymore, its tinc daemon is not running or its connection to the Internet is broken.
2176 @item Received UDP packet from unknown source 1.2.3.4 (port 12345)
2179 @item If you see this only sporadically, it is harmless and caused by a node sending packets using an old key.
2180 @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.
2181 You can add @samp{TCPOnly = yes} to host configuration files to force all VPN traffic to go over a TCP connection.
2184 @item Got bad/bogus/unauthorized REQUEST from foo (1.2.3.4 port 12345)
2187 @item Node foo does not have the right public/private keypair.
2188 Generate new keypairs and distribute them again.
2189 @item An attacker tries to gain access to your VPN.
2190 @item A network error caused corruption of metadata sent from foo.
2195 @c ==================================================================
2196 @node Sending bug reports
2197 @section Sending bug reports
2199 If you really can't find the cause of a problem, or if you suspect tinc is not working right,
2200 you can send us a bugreport, see @ref{Contact information}.
2201 Be sure to include the following information in your bugreport:
2204 @item A clear description of what you are trying to achieve and what the problem is.
2205 @item What platform (operating system, version, hardware architecture) and which version of tinc you use.
2206 @item If compiling tinc fails, a copy of @file{config.log} and the error messages you get.
2207 @item Otherwise, a copy of @file{tinc.conf}, @file{tinc-up} and all files in the @file{hosts/} directory.
2208 @item The output of the commands @samp{ifconfig -a} and @samp{route -n} (or @samp{netstat -rn} if that doesn't work).
2209 @item The output of any command that fails to work as it should (like ping or traceroute).
2212 @c ==================================================================
2213 @node Controlling tinc
2214 @chapter Controlling tinc
2216 @cindex command line interface
2217 You can start, stop, control and inspect a running tincd through the tinc
2218 command. A quick example:
2221 tinc -n @var{netname} reload
2225 If tinc is started without a command, it will act as a shell; it will display a
2226 prompt, and commands can be entered on the prompt. If tinc is compiled with
2227 libreadline, history and command completion are available on the prompt. One
2228 can also pipe a script containing commands through tinc. In that case, lines
2229 starting with a # symbol will be ignored.
2232 * tinc runtime options::
2233 * tinc environment variables::
2240 @c ==================================================================
2241 @node tinc runtime options
2242 @section tinc runtime options
2246 @item -c, --config=@var{path}
2247 Read configuration options from the directory @var{path}. The default is
2248 @file{@value{sysconfdir}/tinc/@var{netname}/}.
2250 @item -n, --net=@var{netname}
2251 Use configuration for net @var{netname}. @xref{Multiple networks}.
2253 @item --pidfile=@var{filename}
2254 Use the cookie from @var{filename} to authenticate with a running tinc daemon.
2255 If unspecified, the default is
2256 @file{@value{localstatedir}/run/tinc.@var{netname}.pid}.
2259 Force some commands to work despite warnings.
2262 Display a short reminder of runtime options and commands, then terminate.
2265 Output version information and exit.
2269 @c ==================================================================
2270 @node tinc environment variables
2271 @section tinc environment variables
2276 If no netname is specified on the command line with the @option{-n} option,
2277 the value of this environment variable is used.
2280 @c ==================================================================
2282 @section tinc commands
2288 @item init [@var{name}]
2289 Create initial configuration files and RSA and Ed25519 keypairs with default length.
2290 If no @var{name} for this node is given, it will be asked for.
2293 @item get @var{variable}
2294 Print the current value of configuration variable @var{variable}.
2295 If more than one variable with the same name exists,
2296 the value of each of them will be printed on a separate line.
2299 @item set @var{variable} @var{value}
2300 Set configuration variable @var{variable} to the given @var{value}.
2301 All previously existing configuration variables with the same name are removed.
2302 To set a variable for a specific host, use the notation @var{host}.@var{variable}.
2305 @item add @var{variable} @var{value}
2306 As above, but without removing any previously existing configuration variables.
2307 If the variable already exists with the given value, nothing happens.
2310 @item del @var{variable} [@var{value}]
2311 Remove configuration variables with the same name and @var{value}.
2312 If no @var{value} is given, all configuration variables with the same name will be removed.
2315 @item edit @var{filename}
2316 Start an editor for the given configuration file.
2317 You do not need to specify the full path to the file.
2321 Export the host configuration file of the local node to standard output.
2325 Export all host configuration files to standard output.
2329 Import host configuration file(s) generated by the tinc export command from standard input.
2330 Already existing host configuration files are not overwritten unless the option --force is used.
2334 The same as export followed by import.
2336 @cindex exchange-all
2338 The same as export-all followed by import.
2341 @item invite @var{name}
2342 Prepares an invitation for a new node with the given @var{name},
2343 and prints a short invitation URL that can be used with the join command.
2346 @item join [@var{URL}]
2347 Join an existing VPN using an invitation URL created using the invite command.
2348 If no @var{URL} is given, it will be read from standard input.
2351 @item start [tincd options]
2352 Start @samp{tincd}, optionally with the given extra options.
2359 @item restart [tincd options]
2360 Restart @samp{tincd}, optionally with the given extra options.
2364 Partially rereads configuration files. Connections to hosts whose host
2365 config files are removed are closed. New outgoing connections specified
2366 in @file{tinc.conf} will be made.
2370 Shows the PID of the currently running @samp{tincd}.
2372 @cindex generate-keys
2373 @item generate-keys [@var{bits}]
2374 Generate both RSA and Ed25519 keypairs (see below) and exit.
2375 tinc will ask where you want to store the files, but will default to the
2376 configuration directory (you can use the -c or -n option).
2378 @cindex generate-ed25519-keys
2379 @item generate-ed25519-keys
2380 Generate public/private Ed25519 keypair and exit.
2382 @cindex generate-rsa-keys
2383 @item generate-rsa-keys [@var{bits}]
2384 Generate public/private RSA keypair and exit. If @var{bits} is omitted, the
2385 default length will be 2048 bits. When saving keys to existing files, tinc
2386 will not delete the old keys; you have to remove them manually.
2389 @item dump [reachable] nodes
2390 Dump a list of all known nodes in the VPN.
2391 If the reachable keyword is used, only lists reachable nodes.
2394 Dump a list of all known connections in the VPN.
2397 Dump a list of all known subnets in the VPN.
2399 @item dump connections
2400 Dump a list of all meta connections with ourself.
2403 @item dump graph | digraph
2404 Dump a graph of the VPN in dotty format.
2405 Nodes are colored according to their reachability:
2406 red nodes are unreachable, orange nodes are indirectly reachable, green nodes are directly reachable.
2407 Black nodes are either directly or indirectly reachable, but direct reachability has not been tried yet.
2410 @item info @var{node} | @var{subnet} | @var{address}
2411 Show information about a particular @var{node}, @var{subnet} or @var{address}.
2412 If an @var{address} is given, any matching subnet will be shown.
2416 Purges all information remembered about unreachable nodes.
2419 @item debug @var{level}
2420 Sets debug level to @var{level}.
2423 @item log [@var{level}]
2424 Capture log messages from a running tinc daemon.
2425 An optional debug level can be given that will be applied only for log messages sent to tinc.
2429 Forces tinc to try to connect to all uplinks immediately.
2430 Usually tinc attempts to do this itself,
2431 but increases the time it waits between the attempts each time it failed,
2432 and if tinc didn't succeed to connect to an uplink the first time after it started,
2433 it defaults to the maximum time of 15 minutes.
2436 @item disconnect @var{node}
2437 Closes the meta connection with the given @var{node}.
2441 If tinc is compiled with libcurses support, this will display live traffic statistics for all the known nodes,
2442 similar to the UNIX top command.
2443 See below for more information.
2447 Dump VPN traffic going through the local tinc node in pcap-savefile format to standard output,
2448 from where it can be redirected to a file or piped through a program that can parse it directly,
2452 @item network [@var{netname}]
2453 If @var{netname} is given, switch to that network.
2454 Otherwise, display a list of all networks for which configuration files exist.
2458 This will check the configuration files for possible problems,
2459 such as unsafe file permissions, missing executable bit on script,
2460 unknown and obsolete configuration variables, wrong public and/or private keys, and so on.
2462 When problems are found, this will be printed on a line with WARNING or ERROR in front of it.
2463 Most problems must be corrected by the user itself, however in some cases (like file permissions and missing public keys),
2464 tinc will ask if it should fix the problem.
2468 @c ==================================================================
2470 @section tinc examples
2472 Examples of some commands:
2475 tinc -n vpn dump graph | circo -Txlib
2476 tinc -n vpn pcap | tcpdump -r -
2480 Examples of changing the configuration using tinc:
2483 tinc -n vpn init foo
2484 tinc -n vpn add Subnet 192.168.1.0/24
2485 tinc -n vpn add bar.Address bar.example.com
2486 tinc -n vpn add ConnectTo bar
2487 tinc -n vpn export | gpg --clearsign | mail -s "My config" vpnmaster@@example.com
2490 @c ==================================================================
2495 The top command connects to a running tinc daemon and repeatedly queries its per-node traffic counters.
2496 It displays a list of all the known nodes in the left-most column,
2497 and the amount of bytes and packets read from and sent to each node in the other columns.
2498 By default, the information is updated every second.
2499 The behaviour of the top command can be changed using the following keys:
2504 Change the interval between updates.
2505 After pressing the @key{s} key, enter the desired interval in seconds, followed by enter.
2506 Fractional seconds are honored.
2507 Intervals lower than 0.1 seconds are not allowed.
2510 Toggle between displaying current traffic rates (in packets and bytes per second)
2511 and cummulative traffic (total packets and bytes since the tinc daemon started).
2514 Sort the list of nodes by name.
2517 Sort the list of nodes by incoming amount of bytes.
2520 Sort the list of nodes by incoming amount of packets.
2523 Sort the list of nodes by outgoing amount of bytes.
2526 Sort the list of nodes by outgoing amount of packets.
2529 Sort the list of nodes by sum of incoming and outgoing amount of bytes.
2532 Sort the list of nodes by sum of incoming and outgoing amount of packets.
2535 Show amount of traffic in bytes.
2538 Show amount of traffic in kilobytes.
2541 Show amount of traffic in megabytes.
2544 Show amount of traffic in gigabytes.
2552 @c ==================================================================
2553 @node Technical information
2554 @chapter Technical information
2559 * The meta-protocol::
2564 @c ==================================================================
2565 @node The connection
2566 @section The connection
2569 Tinc is a daemon that takes VPN data and transmit that to another host
2570 computer over the existing Internet infrastructure.
2574 * The meta-connection::
2578 @c ==================================================================
2579 @node The UDP tunnel
2580 @subsection The UDP tunnel
2582 @cindex virtual network device
2584 The data itself is read from a character device file, the so-called
2585 @emph{virtual network device}. This device is associated with a network
2586 interface. Any data sent to this interface can be read from the device,
2587 and any data written to the device gets sent from the interface.
2588 There are two possible types of virtual network devices:
2589 `tun' style, which are point-to-point devices which can only handle IPv4 and/or IPv6 packets,
2590 and `tap' style, which are Ethernet devices and handle complete Ethernet frames.
2592 So when tinc reads an Ethernet frame from the device, it determines its
2593 type. When tinc is in it's default routing mode, it can handle IPv4 and IPv6
2594 packets. Depending on the Subnet lines, it will send the packets off to their destination IP address.
2595 In the `switch' and `hub' mode, tinc will use broadcasts and MAC address discovery
2596 to deduce the destination of the packets.
2597 Since the latter modes only depend on the link layer information,
2598 any protocol that runs over Ethernet is supported (for instance IPX and Appletalk).
2599 However, only `tap' style devices provide this information.
2601 After the destination has been determined,
2602 the packet will be compressed (optionally),
2603 a sequence number will be added to the packet,
2604 the packet will then be encrypted
2605 and a message authentication code will be appended.
2607 @cindex encapsulating
2609 When that is done, time has come to actually transport the
2610 packet to the destination computer. We do this by sending the packet
2611 over an UDP connection to the destination host. This is called
2612 @emph{encapsulating}, the VPN packet (though now encrypted) is
2613 encapsulated in another IP datagram.
2615 When the destination receives this packet, the same thing happens, only
2616 in reverse. So it checks the message authentication code, decrypts the contents of the UDP datagram,
2617 checks the sequence number
2618 and writes the decrypted information to its own virtual network device.
2620 If the virtual network device is a `tun' device (a point-to-point tunnel),
2621 there is no problem for the kernel to accept a packet.
2622 However, if it is a `tap' device (this is the only available type on FreeBSD),
2623 the destination MAC address must match that of the virtual network interface.
2624 If tinc is in it's default routing mode, ARP does not work, so the correct destination MAC
2625 can not be known by the sending host.
2626 Tinc solves this by letting the receiving end detect the MAC address of its own virtual network interface
2627 and overwriting the destination MAC address of the received packet.
2629 In switch or hub modes ARP does work so the sender already knows the correct destination MAC address.
2630 In those modes every interface should have a unique MAC address, so make sure they are not the same.
2631 Because switch and hub modes rely on MAC addresses to function correctly,
2632 these modes cannot be used on the following operating systems which don't have a `tap' style virtual network device:
2633 OpenBSD, NetBSD, Darwin and Solaris.
2636 @c ==================================================================
2637 @node The meta-connection
2638 @subsection The meta-connection
2640 Having only a UDP connection available is not enough. Though suitable
2641 for transmitting data, we want to be able to reliably send other
2642 information, such as routing and session key information to somebody.
2645 TCP is a better alternative, because it already contains protection
2646 against information being lost, unlike UDP.
2648 So we establish two connections. One for the encrypted VPN data, and one
2649 for other information, the meta-data. Hence, we call the second
2650 connection the meta-connection. We can now be sure that the
2651 meta-information doesn't get lost on the way to another computer.
2653 @cindex data-protocol
2654 @cindex meta-protocol
2655 Like with any communication, we must have a protocol, so that everybody
2656 knows what everything stands for, and how she should react. Because we
2657 have two connections, we also have two protocols. The protocol used for
2658 the UDP data is the ``data-protocol,'' the other one is the
2661 The reason we don't use TCP for both protocols is that UDP is much
2662 better for encapsulation, even while it is less reliable. The real
2663 problem is that when TCP would be used to encapsulate a TCP stream
2664 that's on the private network, for every packet sent there would be
2665 three ACKs sent instead of just one. Furthermore, if there would be
2666 a timeout, both TCP streams would sense the timeout, and both would
2667 start re-sending packets.
2670 @c ==================================================================
2671 @node The meta-protocol
2672 @section The meta-protocol
2674 The meta protocol is used to tie all tinc daemons together, and
2675 exchange information about which tinc daemon serves which virtual
2678 The meta protocol consists of requests that can be sent to the other
2679 side. Each request has a unique number and several parameters. All
2680 requests are represented in the standard ASCII character set. It is
2681 possible to use tools such as telnet or netcat to connect to a tinc
2682 daemon started with the --bypass-security option
2683 and to read and write requests by hand, provided that one
2684 understands the numeric codes sent.
2686 The authentication scheme is described in @ref{Security}. After a
2687 successful authentication, the server and the client will exchange all the
2688 information about other tinc daemons and subnets they know of, so that both
2689 sides (and all the other tinc daemons behind them) have their information
2696 ------------------------------------------------------------------
2697 ADD_EDGE node1 node2 21.32.43.54 655 222 0
2698 | | | | | +-> options
2699 | | | | +----> weight
2700 | | | +--------> UDP port of node2
2701 | | +----------------> real address of node2
2702 | +-------------------------> name of destination node
2703 +-------------------------------> name of source node
2705 ADD_SUBNET node 192.168.1.0/24
2706 | | +--> prefixlength
2707 | +--------> network address
2708 +------------------> owner of this subnet
2709 ------------------------------------------------------------------
2712 The ADD_EDGE messages are to inform other tinc daemons that a connection between
2713 two nodes exist. The address of the destination node is available so that
2714 VPN packets can be sent directly to that node.
2716 The ADD_SUBNET messages inform other tinc daemons that certain subnets belong
2717 to certain nodes. tinc will use it to determine to which node a VPN packet has
2724 ------------------------------------------------------------------
2725 DEL_EDGE node1 node2
2726 | +----> name of destination node
2727 +----------> name of source node
2729 DEL_SUBNET node 192.168.1.0/24
2730 | | +--> prefixlength
2731 | +--------> network address
2732 +------------------> owner of this subnet
2733 ------------------------------------------------------------------
2736 In case a connection between two daemons is closed or broken, DEL_EDGE messages
2737 are sent to inform the other daemons of that fact. Each daemon will calculate a
2738 new route to the the daemons, or mark them unreachable if there isn't any.
2745 ------------------------------------------------------------------
2746 REQ_KEY origin destination
2747 | +--> name of the tinc daemon it wants the key from
2748 +----------> name of the daemon that wants the key
2750 ANS_KEY origin destination 4ae0b0a82d6e0078 91 64 4
2751 | | \______________/ | | +--> MAC length
2752 | | | | +-----> digest algorithm
2753 | | | +--------> cipher algorithm
2754 | | +--> 128 bits key
2755 | +--> name of the daemon that wants the key
2756 +----------> name of the daemon that uses this key
2759 +--> daemon that has changed it's packet key
2760 ------------------------------------------------------------------
2763 The keys used to encrypt VPN packets are not sent out directly. This is
2764 because it would generate a lot of traffic on VPNs with many daemons, and
2765 chances are that not every tinc daemon will ever send a packet to every
2766 other daemon. Instead, if a daemon needs a key it sends a request for it
2767 via the meta connection of the nearest hop in the direction of the
2774 ------------------------------------------------------------------
2777 ------------------------------------------------------------------
2780 There is also a mechanism to check if hosts are still alive. Since network
2781 failures or a crash can cause a daemon to be killed without properly
2782 shutting down the TCP connection, this is necessary to keep an up to date
2783 connection list. PINGs are sent at regular intervals, except when there
2784 is also some other traffic. A little bit of salt (random data) is added
2785 with each PING and PONG message, to make sure that long sequences of PING/PONG
2786 messages without any other traffic won't result in known plaintext.
2788 This basically covers what is sent over the meta connection by tinc.
2791 @c ==================================================================
2797 Tinc got its name from ``TINC,'' short for @emph{There Is No Cabal}; the
2798 alleged Cabal was/is an organisation that was said to keep an eye on the
2799 entire Internet. As this is exactly what you @emph{don't} want, we named
2800 the tinc project after TINC.
2803 But in order to be ``immune'' to eavesdropping, you'll have to encrypt
2804 your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does
2805 exactly that: encrypt.
2806 However, encryption in itself does not prevent an attacker from modifying the encrypted data.
2807 Therefore, tinc also authenticates the data.
2808 Finally, tinc uses sequence numbers (which themselves are also authenticated) to prevent an attacker from replaying valid packets.
2810 Since version 1.1pre3, tinc has two protocols used to protect your data; the legacy protocol, and the new Simple Peer-to-Peer Security (SPTPS) protocol.
2811 The SPTPS protocol is designed to address some weaknesses in the legacy protocol.
2812 The new authentication protocol is used when two nodes connect to each other that both have the ExperimentalProtocol option set to yes,
2813 otherwise the legacy protocol will be used.
2816 * Legacy authentication protocol::
2817 * Simple Peer-to-Peer Security::
2818 * Encryption of network packets::
2823 @c ==================================================================
2824 @node Legacy authentication protocol
2825 @subsection Legacy authentication protocol
2827 @cindex legacy authentication protocol
2836 --------------------------------------------------------------------------
2837 client <attempts connection>
2839 server <accepts connection>
2841 client ID client 17.2
2842 | | +-> minor protocol version
2843 | +----> major protocol version
2844 +--------> name of tinc daemon
2846 server ID server 17.2
2847 | | +-> minor protocol version
2848 | +----> major protocol version
2849 +--------> name of tinc daemon
2851 client META_KEY 94 64 0 0 5f0823a93e35b69e...7086ec7866ce582b
2852 | | | | \_________________________________/
2853 | | | | +-> RSAKEYLEN bits totally random string S1,
2854 | | | | encrypted with server's public RSA key
2855 | | | +-> compression level
2856 | | +---> MAC length
2857 | +------> digest algorithm NID
2858 +---------> cipher algorithm NID
2860 server META_KEY 94 64 0 0 6ab9c1640388f8f0...45d1a07f8a672630
2861 | | | | \_________________________________/
2862 | | | | +-> RSAKEYLEN bits totally random string S2,
2863 | | | | encrypted with client's public RSA key
2864 | | | +-> compression level
2865 | | +---> MAC length
2866 | +------> digest algorithm NID
2867 +---------> cipher algorithm NID
2868 --------------------------------------------------------------------------
2871 The protocol allows each side to specify encryption algorithms and parameters,
2872 but in practice they are always fixed, since older versions of tinc did not
2873 allow them to be different from the default values. The cipher is always
2874 Blowfish in OFB mode, the digest is SHA1, but the MAC length is zero and no
2875 compression is used.
2879 @item the client will symmetrically encrypt outgoing traffic using S1
2880 @item the server will symmetrically encrypt outgoing traffic using S2
2884 --------------------------------------------------------------------------
2885 client CHALLENGE da02add1817c1920989ba6ae2a49cecbda0
2886 \_________________________________/
2887 +-> CHALLEN bits totally random string H1
2889 server CHALLENGE 57fb4b2ccd70d6bb35a64c142f47e61d57f
2890 \_________________________________/
2891 +-> CHALLEN bits totally random string H2
2893 client CHAL_REPLY 816a86
2894 +-> 160 bits SHA1 of H2
2896 server CHAL_REPLY 928ffe
2897 +-> 160 bits SHA1 of H1
2899 After the correct challenge replies are received, both ends have proved
2900 their identity. Further information is exchanged.
2902 client ACK 655 123 0
2904 | +----> estimated weight
2905 +--------> listening port of client
2907 server ACK 655 321 0
2909 | +----> estimated weight
2910 +--------> listening port of server
2911 --------------------------------------------------------------------------
2914 This legacy authentication protocol has several weaknesses, pointed out by security export Peter Gutmann.
2915 First, data is encrypted with RSA without padding.
2916 Padding schemes are designed to prevent attacks when the size of the plaintext is not equal to the size of the RSA key.
2917 Tinc always encrypts random nonces that have the same size as the RSA key, so we do not believe this leads to a break of the security.
2918 There might be timing or other side-channel attacks against RSA encryption and decryption, tinc does not employ any protection against those.
2919 Furthermore, both sides send identical messages to each other, there is no distinction between server and client,
2920 which could make a MITM attack easier.
2921 However, no exploit is known in which a third party who is not already trusted by other nodes in the VPN could gain access.
2922 Finally, the RSA keys are used to directly encrypt the session keys, which means that if the RSA keys are compromised, it is possible to decrypt all previous VPN traffic.
2923 In other words, the legacy protocol does not provide perfect forward secrecy.
2925 @c ==================================================================
2926 @node Simple Peer-to-Peer Security
2927 @subsection Simple Peer-to-Peer Security
2930 The SPTPS protocol is designed to address the weaknesses in the legacy protocol.
2931 SPTPS is based on TLS 1.2, but has been simplified: there is no support for exchanging public keys, and there is no cipher suite negotiation.
2932 Instead, SPTPS always uses a very strong cipher suite:
2933 peers authenticate each other using 521 bits ECC keys,
2934 Diffie-Hellman using ephemeral 521 bits ECC keys is used to provide perfect forward secrecy (PFS),
2935 AES-256-CTR is used for encryption, and HMAC-SHA-256 for message authentication.
2937 Similar to TLS, messages are split up in records.
2938 A complete logical record contains the following information:
2941 @item uint32_t seqno (network byte order)
2942 @item uint16_t length (network byte order)
2944 @item opaque data[length]
2945 @item opaque hmac[HMAC_SIZE] (HMAC over all preceding fields)
2948 Depending on whether SPTPS records are sent via TCP or UDP, either the seqno or the length field is omitted on the wire
2949 (but they are still included in the calculation of the HMAC);
2950 for TCP packets are guaranteed to arrive in-order so we can infer the seqno, but packets can be split or merged, so we still need the length field to determine the boundaries between records;
2951 for UDP packets we know that there is exactly one record per packet, and we know the length of a packet, but packets can be dropped, duplicated and/or reordered, so we need to include the seqno.
2953 The type field is used to distinguish between application records or handshake records.
2954 Types 0 to 127 are application records, type 128 is a handshake record, and types 129 to 255 are reserved.
2956 Before the initial handshake, no fields are encrypted, and the HMAC field is not present.
2957 After the authentication handshake, the length (if present), type and data fields are encrypted, and the HMAC field is present.
2958 For UDP packets, the seqno field is not encrypted, as it is used to determine the value of the counter used for encryption.
2960 The authentication consists of an exchange of Key EXchange, SIGnature and ACKnowledge messages, transmitted using type 128 records.
2966 ---------------------
2972 ...encrypt and HMAC using session keys from now on...
2979 ...key renegotiation starts here...
2988 ...encrypt and HMAC using new session keys from now on...
2994 ---------------------
2997 Note that the responder does not need to wait before it receives the first KEX message,
2998 it can immediately send its own once it has accepted an incoming connection.
3000 Key EXchange message:
3003 @item uint8_t kex_version (always 0 in this version of SPTPS)
3004 @item opaque nonce[32] (random number)
3005 @item opaque ecdh_key[ECDH_SIZE]
3011 @item opaque ecdsa_signature[ECDSA_SIZE]
3014 ACKnowledge message:
3017 @item empty (only sent after key renegotiation)
3023 @item At the start, both peers generate a random nonce and an Elliptic Curve public key and send it to the other in the KEX message.
3024 @item After receiving the other's KEX message, both KEX messages are concatenated (see below),
3025 and the result is signed using ECDSA.
3026 The result is sent to the other.
3027 @item After receiving the other's SIG message, the signature is verified.
3028 If it is correct, the shared secret is calculated from the public keys exchanged in the KEX message using the Elliptic Curve Diffie-Helman algorithm.
3029 @item The shared secret key is expanded using a PRF.
3030 Both nonces and the application specific label are also used as input for the PRF.
3031 @item An ACK message is sent only when doing key renegotiation, and is sent using the old encryption keys.
3032 @item The expanded key is used to key the encryption and HMAC algorithms.
3035 The signature is calculated over this string:
3038 @item uint8_t initiator (0 = local peer, 1 = remote peer is initiator)
3039 @item opaque remote_kex_message[1 + 32 + ECDH_SIZE]
3040 @item opaque local_kex_message[1 + 32 + ECDH_SIZE]
3041 @item opaque label[label_length]
3044 The PRF is calculated as follows:
3047 @item A HMAC using SHA512 is used, the shared secret is used as the key.
3048 @item For each block of 64 bytes, a HMAC is calculated. For block n: hmac[n] =
3049 HMAC_SHA512(hmac[n - 1] + seed)
3050 @item For the first block (n = 1), hmac[0] is given by HMAC_SHA512(zeroes + seed),
3051 where zeroes is a block of 64 zero bytes.
3054 The seed is as follows:
3057 @item const char[13] "key expansion"
3058 @item opaque responder_nonce[32]
3059 @item opaque initiator_nonce[32]
3060 @item opaque label[label_length]
3063 The expanded key is used as follows:
3066 @item opaque responder_cipher_key[CIPHER_KEYSIZE]
3067 @item opaque responder_digest_key[DIGEST_KEYSIZE]
3068 @item opaque initiator_cipher_key[CIPHER_KEYSIZE]
3069 @item opaque initiator_digest_key[DIGEST_KEYSIZE]
3072 Where initiator_cipher_key is the key used by session initiator to encrypt
3073 messages sent to the responder.
3075 When using 256 bits Ed25519 keys, the AES-256-CTR cipher and HMAC-SHA-256 digest algorithm,
3076 the sizes are as follows:
3079 ECDH_SIZE: 32 (= 256/8)
3080 ECDSA_SIZE: 64 (= 2 * 256/8)
3081 CIPHER_KEYSIZE: 48 (= 256/8 + 128/8)
3082 DIGEST_KEYSIZE: 32 (= 256/8)
3085 Note that the cipher key also includes the initial value for the counter.
3087 @c ==================================================================
3088 @node Encryption of network packets
3089 @subsection Encryption of network packets
3092 A data packet can only be sent if the encryption key is known to both
3093 parties, and the connection is activated. If the encryption key is not
3094 known, a request is sent to the destination using the meta connection
3098 The UDP packets can be either encrypted with the legacy protocol or with SPTPS.
3099 In case of the legacy protocol, the UDP packet containing the network packet from the VPN has the following layout:
3102 ... | IP header | UDP header | seqno | VPN packet | MAC | UDP trailer
3103 \___________________/\_____/
3105 V +---> digest algorithm
3106 Encrypted with symmetric cipher
3112 So, the entire VPN packet is encrypted using a symmetric cipher, including a 32 bits
3113 sequence number that is added in front of the actual VPN packet, to act as a unique
3114 IV for each packet and to prevent replay attacks. A message authentication code
3115 is added to the UDP packet to prevent alteration of packets.
3116 Tinc by default encrypts network packets using Blowfish with 128 bit keys in CBC mode
3117 and uses 4 byte long message authentication codes to make sure
3118 eavesdroppers cannot get and cannot change any information at all from the
3119 packets they can intercept. The encryption algorithm and message authentication
3120 algorithm can be changed in the configuration. The length of the message
3121 authentication codes is also adjustable. The length of the key for the
3122 encryption algorithm is always the default length used by OpenSSL.
3124 The SPTPS protocol is described in @ref{Simple Peer-to-Peer Security}.
3125 For comparison, this is how SPTPS UDP packets look:
3128 ... | IP header | UDP header | seqno | type | VPN packet | MAC | UDP trailer
3129 \__________________/\_____/
3131 V +---> digest algorithm
3132 Encrypted with symmetric cipher
3135 The difference is that the seqno is not encrypted, since the encryption cipher is used in CTR mode,
3136 and therefore the seqno must be known before the packet can be decrypted.
3137 Furthermore, the MAC is never truncated.
3138 The SPTPS protocol always uses the AES-256-CTR cipher and HMAC-SHA-256 digest,
3139 this cannot be changed.
3142 @c ==================================================================
3143 @node Security issues
3144 @subsection Security issues
3146 In August 2000, we discovered the existence of a security hole in all versions
3147 of tinc up to and including 1.0pre2. This had to do with the way we exchanged
3148 keys. Since then, we have been working on a new authentication scheme to make
3149 tinc as secure as possible. The current version uses the OpenSSL library and
3150 uses strong authentication with RSA keys.
3152 On the 29th of December 2001, Jerome Etienne posted a security analysis of tinc
3153 1.0pre4. Due to a lack of sequence numbers and a message authentication code
3154 for each packet, an attacker could possibly disrupt certain network services or
3155 launch a denial of service attack by replaying intercepted packets. The current
3156 version adds sequence numbers and message authentication codes to prevent such
3159 On the 15th of September 2003, Peter Gutmann posted a security analysis of tinc
3160 1.0.1. He argues that the 32 bit sequence number used by tinc is not a good IV,
3161 that tinc's default length of 4 bytes for the MAC is too short, and he doesn't
3162 like tinc's use of RSA during authentication. We do not know of a security hole
3163 in the legacy protocol of tinc, but it is not as strong as TLS or IPsec.
3165 This version of tinc comes with an improved protocol, called Simple Peer-to-Peer Security,
3166 which aims to be as strong as TLS with one of the strongest cipher suites.
3168 Cryptography is a hard thing to get right. We cannot make any
3169 guarantees. Time, review and feedback are the only things that can
3170 prove the security of any cryptographic product. If you wish to review
3171 tinc or give us feedback, you are stronly encouraged to do so.
3174 @c ==================================================================
3175 @node Platform specific information
3176 @chapter Platform specific information
3179 * Interface configuration::
3183 @c ==================================================================
3184 @node Interface configuration
3185 @section Interface configuration
3187 When configuring an interface, one normally assigns it an address and a
3188 netmask. The address uniquely identifies the host on the network attached to
3189 the interface. The netmask, combined with the address, forms a subnet. It is
3190 used to add a route to the routing table instructing the kernel to send all
3191 packets which fall into that subnet to that interface. Because all packets for
3192 the entire VPN should go to the virtual network interface used by tinc, the
3193 netmask should be such that it encompasses the entire VPN.
3197 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
3199 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
3200 @item Linux iproute2
3201 @tab @code{ip addr add} @var{address}@code{/}@var{prefixlength} @code{dev} @var{interface}
3203 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
3205 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
3207 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
3209 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
3210 @item Darwin (MacOS/X)
3211 @tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
3213 @tab @code{netsh interface ip set address} @var{interface} @code{static} @var{address} @var{netmask}
3218 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
3220 @tab @code{ifconfig} @var{interface} @code{add} @var{address}@code{/}@var{prefixlength}
3222 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
3224 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
3226 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
3228 @tab @code{ifconfig} @var{interface} @code{inet6 plumb up}
3230 @tab @code{ifconfig} @var{interface} @code{inet6 addif} @var{address} @var{address}
3231 @item Darwin (MacOS/X)
3232 @tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
3234 @tab @code{netsh interface ipv6 add address} @var{interface} @code{static} @var{address}/@var{prefixlength}
3237 On some platforms, when running tinc in switch mode, the VPN interface must be set to tap mode with an ifconfig command:
3239 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
3241 @tab @code{ifconfig} @var{interface} @code{link0}
3244 On Linux, it is possible to create a persistent tun/tap interface which will
3245 continue to exist even if tinc quit, although this is normally not required.
3246 It can be useful to set up a tun/tap interface owned by a non-root user, so
3247 tinc can be started without needing any root privileges at all.
3249 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
3251 @tab @code{ip tuntap add dev} @var{interface} @code{mode} @var{tun|tap} @code{user} @var{username}
3254 @c ==================================================================
3258 In some cases it might be necessary to add more routes to the virtual network
3259 interface. There are two ways to indicate which interface a packet should go
3260 to, one is to use the name of the interface itself, another way is to specify
3261 the (local) address that is assigned to that interface (@var{local_address}). The
3262 former way is unambiguous and therefore preferable, but not all platforms
3265 Adding routes to IPv4 subnets:
3267 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
3269 @tab @code{route add -net} @var{network_address} @code{netmask} @var{netmask} @var{interface}
3270 @item Linux iproute2
3271 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
3273 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
3275 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
3277 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
3279 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
3280 @item Darwin (MacOS/X)
3281 @tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
3283 @tab @code{netsh routing ip add persistentroute} @var{network_address} @var{netmask} @var{interface} @var{local_address}
3286 Adding routes to IPv6 subnets:
3288 @multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
3290 @tab @code{route add -A inet6} @var{network_address}@code{/}@var{prefixlength} @var{interface}
3291 @item Linux iproute2
3292 @tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
3294 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
3296 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
3298 @tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
3300 @tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
3301 @item Darwin (MacOS/X)
3304 @tab @code{netsh interface ipv6 add route} @var{network address}/@var{prefixlength} @var{interface}
3308 @c ==================================================================
3314 * Contact information::
3319 @c ==================================================================
3320 @node Contact information
3321 @section Contact information
3324 Tinc's website is at @url{http://www.tinc-vpn.org/},
3325 this server is located in the Netherlands.
3328 We have an IRC channel on the FreeNode and OFTC IRC networks. Connect to
3329 @uref{http://www.freenode.net/, irc.freenode.net}
3331 @uref{http://www.oftc.net/, irc.oftc.net}
3332 and join channel #tinc.
3335 @c ==================================================================
3340 @item Ivo Timmermans (zarq)
3341 @item Guus Sliepen (guus) (@email{guus@@tinc-vpn.org})
3344 We have received a lot of valuable input from users. With their help,
3345 tinc has become the flexible and robust tool that it is today. We have
3346 composed a list of contributions, in the file called @file{THANKS} in
3347 the source distribution.
3350 @c ==================================================================
3352 @unnumbered Concept Index
3354 @c ==================================================================
3358 @c ==================================================================