\input texinfo @c -*-texinfo-*-
@c %**start of header
-@setfilename tinc.info
-@settitle tinc Manual
+@setfilename meshlink.info
+@settitle MeshLink Manual
@setchapternewpage odd
@c %**end of header
@ifinfo
@dircategory Networking tools
@direntry
-* tinc: (tinc). The tinc Manual.
+* MeshLink: (MeshLink). The MeshLink library.
@end direntry
-This is the info manual for @value{PACKAGE} version @value{VERSION}, a Virtual Private Network daemon.
+This is the info manual for the MeshLink library version @value{VERSION}.
-Copyright @copyright{} 1998-2014 Ivo Timmermans,
-Guus Sliepen <guus@@tinc-vpn.org> and
-Wessel Dankers <wsl@@tinc-vpn.org>.
+Copyright @copyright{} 2014 Guus Sliepen <guus@@tinc-vpn.org>.
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.
-
@end ifinfo
@afourpaper
@finalout
@titlepage
-@title tinc Manual
-@subtitle Setting up a Virtual Private Network with tinc
-@author Ivo Timmermans and Guus Sliepen
+@title The MeshLink library
+@author Guus Sliepen
@page
@vskip 0pt plus 1filll
-This is the info manual for @value{PACKAGE} version @value{VERSION}, a Virtual Private Network daemon.
+This is the info manual for the MeshLink library version @value{VERSION}.
-Copyright @copyright{} 1998-2014 Ivo Timmermans,
-Guus Sliepen <guus@@tinc-vpn.org> and
-Wessel Dankers <wsl@@tinc-vpn.org>.
+Copyright @copyright{} 2014 Guus Sliepen <guus@@tinc-vpn.org>
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.
-
@end titlepage
@ifnottex
@menu
* Introduction::
-* Preparations::
-* Installation::
-* Configuration::
-* Running tinc::
-* Controlling tinc::
-* Technical information::
-* Platform specific information::
* About us::
* Concept Index:: All used terms explained
@end menu
@node Introduction
@chapter Introduction
-@cindex tinc
-Tinc is a Virtual Private Network (VPN) daemon that uses tunneling and
-encryption to create a secure private network between hosts on the
-Internet.
-
-Because the tunnel appears to the IP level network code as a normal
-network device, there is no need to adapt any existing software.
-The encrypted tunnels allows VPN sites to share information with each other
-over the Internet without exposing any information to others.
-
-This document is the manual for tinc. Included are chapters on how to
-configure your computer to use tinc, as well as the configuration
-process of tinc itself.
-
-@menu
-* Virtual Private Networks::
-* tinc:: About tinc
-* Supported platforms::
-@end menu
-
-@c ==================================================================
-@node Virtual Private Networks
-@section Virtual Private Networks
-
-@cindex VPN
-A Virtual Private Network or VPN is a network that can only be accessed
-by a few elected computers that participate. This goal is achievable in
-more than just one way.
-
-@cindex private
-Private networks can consist of a single stand-alone Ethernet LAN. Or
-even two computers hooked up using a null-modem cable. In these cases,
-it is
-obvious that the network is @emph{private}, no one can access it from the
-outside. But if your computers are linked to the Internet, the network
-is not private anymore, unless one uses firewalls to block all private
-traffic. But then, there is no way to send private data to trusted
-computers on the other end of the Internet.
-
-@cindex virtual
-This problem can be solved by using @emph{virtual} networks. Virtual
-networks can live on top of other networks, but they use encapsulation to
-keep using their private address space so they do not interfere with
-the Internet. Mostly, virtual networks appear like a single LAN, even though
-they can span the entire world. But virtual networks can't be secured
-by using firewalls, because the traffic that flows through it has to go
-through the Internet, where other people can look at it.
-
-As is the case with either type of VPN, anybody could eavesdrop. Or
-worse, alter data. Hence it's probably advisable to encrypt the data
-that flows over the network.
-
-When one introduces encryption, we can form a true VPN. Other people may
-see encrypted traffic, but if they don't know how to decipher it (they
-need to know the key for that), they cannot read the information that flows
-through the VPN. This is what tinc was made for.
-
-
-@c ==================================================================
-@node tinc
-@section tinc
-
-@cindex vpnd
-I really don't quite remember what got us started, but it must have been
-Guus' idea. He wrote a simple implementation (about 50 lines of C) that
-used the ethertap device that Linux knows of since somewhere
-about kernel 2.1.60. It didn't work immediately and he improved it a
-bit. At this stage, the project was still simply called "vpnd".
-
-Since then, a lot has changed---to say the least.
-
-@cindex tincd
-Tinc now supports encryption, it consists of a single daemon (tincd) for
-both the receiving and sending end, it has become largely
-runtime-configurable---in short, it has become a full-fledged
-professional package.
-
-@cindex traditional VPNs
-@cindex scalability
-Tinc also allows more than two sites to connect to eachother and form a single VPN.
-Traditionally VPNs are created by making tunnels, which only have two endpoints.
-Larger VPNs with more sites are created by adding more tunnels.
-Tinc takes another approach: only endpoints are specified,
-the software itself will take care of creating the tunnels.
-This allows for easier configuration and improved scalability.
-
-A lot can---and will be---changed. We have a number of things that we would like to
-see in the future releases of tinc. Not everything will be available in
-the near future. Our first objective is to make tinc work perfectly as
-it stands, and then add more advanced features.
-
-Meanwhile, we're always open-minded towards new ideas. And we're
-available too.
-
-
-@c ==================================================================
-@node Supported platforms
-@section Supported platforms
-
-@cindex platforms
-Tinc has been verified to work under Linux, FreeBSD, OpenBSD, NetBSD, MacOS/X (Darwin), Solaris, and Windows (both natively and in a Cygwin environment),
-with various hardware architectures. These are some of the platforms
-that are supported by the universal tun/tap device driver or other virtual network device drivers.
-Without such a driver, tinc will most
-likely compile and run, but it will not be able to send or receive data
-packets.
-
-@cindex release
-For an up to date list of supported platforms, please check the list on
-our website:
-@uref{http://www.tinc-vpn.org/platforms/}.
-
-@c
-@c
-@c
-@c
-@c
-@c
-@c Preparing your system
-@c
-@c
-@c
-@c
-@c
-
-@c ==================================================================
-@node Preparations
-@chapter Preparations
-
-This chapter contains information on how to prepare your system to
-support tinc.
-
-@menu
-* Configuring the kernel::
-* Libraries::
-@end menu
-
-
-@c ==================================================================
-@node Configuring the kernel
-@section Configuring the kernel
-
-@menu
-* Configuration of Linux kernels::
-* Configuration of FreeBSD kernels::
-* Configuration of OpenBSD kernels::
-* Configuration of NetBSD kernels::
-* Configuration of Solaris kernels::
-* Configuration of Darwin (MacOS/X) kernels::
-* Configuration of Windows::
-@end menu
-
-
-@c ==================================================================
-@node Configuration of Linux kernels
-@subsection Configuration of Linux kernels
-
-@cindex Universal tun/tap
-For tinc to work, you need a kernel that supports the Universal tun/tap device.
-Most distributions come with kernels that already support this.
-Here are the options you have to turn on when configuring a new kernel:
-
-@example
-Code maturity level options
-[*] Prompt for development and/or incomplete code/drivers
-Network device support
-<M> Universal tun/tap device driver support
-@end example
-
-It's not necessary to compile this driver as a module, even if you are going to
-run more than one instance of tinc.
-
-If you decide to build the tun/tap driver as a kernel module, add these lines
-to @file{/etc/modules.conf}:
-
-@example
-alias char-major-10-200 tun
-@end example
-
-
-@c ==================================================================
-@node Configuration of FreeBSD kernels
-@subsection Configuration of FreeBSD kernels
-
-For FreeBSD version 4.1 and higher, tun and tap drivers are included in the default kernel configuration.
-The tap driver can be loaded with @code{kldload if_tap}, or by adding @code{if_tap_load="YES"} to @file{/boot/loader.conf}.
-
-
-@c ==================================================================
-@node Configuration of OpenBSD kernels
-@subsection Configuration of OpenBSD kernels
-
-For OpenBSD version 2.9 and higher,
-the tun driver is included in the default kernel configuration.
-There is also a kernel patch from @uref{http://diehard.n-r-g.com/stuff/openbsd/}
-which adds a tap device to OpenBSD which should work with tinc,
-but with recent versions of OpenBSD,
-a tun device can act as a tap device by setting the link0 option with ifconfig.
-
-
-@c ==================================================================
-@node Configuration of NetBSD kernels
-@subsection Configuration of NetBSD kernels
-
-For NetBSD version 1.5.2 and higher,
-the tun driver is included in the default kernel configuration.
-
-Tunneling IPv6 may not work on NetBSD's tun device.
-
-
-@c ==================================================================
-@node Configuration of Solaris kernels
-@subsection Configuration of Solaris kernels
-
-For Solaris 8 (SunOS 5.8) and higher,
-the tun driver may or may not be included in the default kernel configuration.
-If it isn't, the source can be downloaded from @uref{http://vtun.sourceforge.net/tun/}.
-For x86 and sparc64 architectures, precompiled versions can be found at @uref{http://www.monkey.org/~dugsong/fragroute/}.
-If the @file{net/if_tun.h} header file is missing, install it from the source package.
-
-
-@c ==================================================================
-@node Configuration of Darwin (MacOS/X) kernels
-@subsection Configuration of Darwin (MacOS/X) kernels
-
-Tinc on Darwin relies on a tunnel driver for its data acquisition from the kernel.
-Tinc supports either the driver from @uref{http://tuntaposx.sourceforge.net/},
-which supports both tun and tap style devices,
-and also the driver from from @uref{http://chrisp.de/en/projects/tunnel.html}.
-The former driver is recommended.
-The tunnel driver must be loaded before starting tinc with the following command:
-
-@example
-kmodload tunnel
-@end example
-
-
-@c ==================================================================
-@node Configuration of Windows
-@subsection Configuration of Windows
-
-You will need to install the latest TAP-Win32 driver from OpenVPN.
-You can download it from @uref{http://openvpn.sourceforge.net}.
-Using the Network Connections control panel,
-configure the TAP-Win32 network interface in the same way as you would do from the tinc-up script,
-as explained in the rest of the documentation.
-
-
-@c ==================================================================
-@node Libraries
-@section Libraries
-
-@cindex requirements
-@cindex libraries
-Before you can configure or build tinc, you need to have the OpenSSL, zlib,
-lzo, curses and readline libraries installed on your system. If you try to
-configure tinc without having them installed, configure will give you an error
-message, and stop.
-
-@menu
-* OpenSSL::
-* zlib::
-* lzo::
-* libcurses::
-* libreadline::
-@end menu
-
-
-@c ==================================================================
-@node OpenSSL
-@subsection OpenSSL
-
-@cindex OpenSSL
-For all cryptography-related functions, tinc uses the functions provided
-by the OpenSSL library.
-
-If this library is not installed, you wil get an error when configuring
-tinc for build. Support for running tinc with other cryptographic libraries
-installed @emph{may} be added in the future.
-
-You can use your operating system's package manager to install this if
-available. Make sure you install the development AND runtime versions
-of this package.
-
-If you have to install OpenSSL manually, you can get the source code
-from @url{http://www.openssl.org/}. Instructions on how to configure,
-build and install this package are included within the package. Please
-make sure you build development and runtime libraries (which is the
-default).
-
-If you installed the OpenSSL libraries from source, it may be necessary
-to let configure know where they are, by passing configure one of the
---with-openssl-* parameters.
-
-@example
---with-openssl=DIR OpenSSL library and headers prefix
---with-openssl-include=DIR OpenSSL headers directory
- (Default is OPENSSL_DIR/include)
---with-openssl-lib=DIR OpenSSL library directory
- (Default is OPENSSL_DIR/lib)
-@end example
-
-
-@subsubheading License
-
-@cindex license
-The complete source code of tinc is covered by the GNU GPL version 2.
-Since the license under which OpenSSL is distributed is not directly
-compatible with the terms of the GNU GPL
-@uref{http://www.openssl.org/support/faq.html#LEGAL2}, we
-include an exemption to the GPL (see also the file COPYING.README) to allow
-everyone to create a statically or dynamically linked executable:
-
-@quotation
-This program is released under the GPL with the additional exemption
-that compiling, linking, and/or using OpenSSL is allowed. You may
-provide binary packages linked to the OpenSSL libraries, provided that
-all other requirements of the GPL are met.
-@end quotation
-
-Since the LZO library used by tinc is also covered by the GPL,
-we also present the following exemption:
-
-@quotation
-Hereby I grant a special exception to the tinc VPN project
-(http://www.tinc-vpn.org/) to link the LZO library with the OpenSSL library
-(http://www.openssl.org).
-
-Markus F.X.J. Oberhumer
-@end quotation
-
-
-@c ==================================================================
-@node zlib
-@subsection zlib
-
-@cindex zlib
-For the optional compression of UDP packets, tinc uses the functions provided
-by the zlib library.
-
-If this library is not installed, you wil get an error when running the
-configure script. You can either install the zlib library, or disable support
-for zlib compression by using the "--disable-zlib" option when running the
-configure script. Note that if you disable support for zlib, the resulting
-binary will not work correctly on VPNs where zlib compression is used.
-
-You can use your operating system's package manager to install this if
-available. Make sure you install the development AND runtime versions
-of this package.
-
-If you have to install zlib manually, you can get the source code
-from @url{http://www.gzip.org/zlib/}. Instructions on how to configure,
-build and install this package are included within the package. Please
-make sure you build development and runtime libraries (which is the
-default).
-
-
-@c ==================================================================
-@node lzo
-@subsection lzo
-
-@cindex lzo
-Another form of compression is offered using the LZO library.
-
-If this library is not installed, you wil get an error when running the
-configure script. You can either install the LZO library, or disable support
-for LZO compression by using the "--disable-lzo" option when running the
-configure script. Note that if you disable support for LZO, the resulting
-binary will not work correctly on VPNs where LZO compression is used.
-
-You can use your operating system's package manager to install this if
-available. Make sure you install the development AND runtime versions
-of this package.
-
-If you have to install lzo manually, you can get the source code
-from @url{http://www.oberhumer.com/opensource/lzo/}. Instructions on how to configure,
-build and install this package are included within the package. Please
-make sure you build development and runtime libraries (which is the
-default).
-
-
-@c ==================================================================
-@node libcurses
-@subsection libcurses
-
-@cindex libcurses
-For the "tinc top" command, tinc requires a curses library.
-
-If this library is not installed, you wil get an error when running the
-configure script. You can either install a suitable curses library, or disable
-all functionality that depends on a curses library by using the
-"--disable-curses" option when running the configure script.
-
-There are several curses libraries. It is recommended that you install
-"ncurses" (@url{http://invisible-island.net/ncurses/}),
-however other curses libraries should also work.
-In particular, "PDCurses" (@url{http://pdcurses.sourceforge.net/})
-is recommended if you want to compile tinc for Windows.
-
-You can use your operating system's package manager to install this if
-available. Make sure you install the development AND runtime versions
-of this package.
-
-
-@c ==================================================================
-@node libreadline
-@subsection libreadline
-
-@cindex libreadline
-For the "tinc" command's shell functionality, tinc uses the readline library.
-
-If this library is not installed, you wil get an error when running the
-configure script. You can either install a suitable readline library, or
-disable all functionality that depends on a readline library by using the
-"--disable-readline" option when running the configure script.
-
-You can use your operating system's package manager to install this if
-available. Make sure you install the development AND runtime versions
-of this package.
-
-If you have to install libreadline manually, you can get the source code from
-@url{http://www.gnu.org/software/readline/}. Instructions on how to configure,
-build and install this package are included within the package. Please make
-sure you build development and runtime libraries (which is the default).
-
-
-@c
-@c
-@c
-@c Installing tinc
-@c
-@c
-@c
-@c
+The MeshLink library allows applications that link to it to connect to other
+instances of itself, and exchange messages in a secure way. MeshLink provides
+end-to-end encryption and authentication of messages with perfect forward
+secrecy. The MeshLink library starts its own thread which handles all network
+communications. The application only needs to register callbacks to get
+notified of incoming messages and other important events.
-@c ==================================================================
-@node Installation
-@chapter Installation
-
-If you use Debian, you may want to install one of the
-precompiled packages for your system. These packages are equipped with
-system startup scripts and sample configurations.
-
-If you cannot use one of the precompiled packages, or you want to compile tinc
-for yourself, you can use the source. The source is distributed under
-the GNU General Public License (GPL). Download the source from the
-@uref{http://www.tinc-vpn.org/download/, download page}, which has
-the checksums of these files listed; you may wish to check these with
-md5sum before continuing.
-
-Tinc comes in a convenient autoconf/automake package, which you can just
-treat the same as any other package. Which is just untar it, type
-`./configure' and then `make'.
-More detailed instructions are in the file @file{INSTALL}, which is
-included in the source distribution.
-
-@menu
-* Building and installing tinc::
-* System files::
-@end menu
-
-
-@c ==================================================================
-@node Building and installing tinc
-@section Building and installing tinc
-
-Detailed instructions on configuring the source, building tinc and installing tinc
-can be found in the file called @file{INSTALL}.
-
-@cindex binary package
-If you happen to have a binary package for tinc for your distribution,
-you can use the package management tools of that distribution to install tinc.
-The documentation that comes along with your distribution will tell you how to do that.
-
-@menu
-* Darwin (MacOS/X) build environment::
-* Cygwin (Windows) build environment::
-* MinGW (Windows) build environment::
-@end menu
-
-
-@c ==================================================================
-@node Darwin (MacOS/X) build environment
-@subsection Darwin (MacOS/X) build environment
-
-In order to build tinc on Darwin, you need to install the MacOS/X Developer Tools
-from @uref{http://developer.apple.com/tools/macosxtools.html} and
-a recent version of Fink from @uref{http://www.finkproject.org/}.
-
-After installation use fink to download and install the following packages:
-autoconf25, automake, dlcompat, m4, openssl, zlib and lzo.
-
-@c ==================================================================
-@node Cygwin (Windows) build environment
-@subsection Cygwin (Windows) build environment
-
-If Cygwin hasn't already been installed, install it directly from
-@uref{http://www.cygwin.com/}.
-
-When tinc is compiled in a Cygwin environment, it can only be run in this environment,
-but all programs, including those started outside the Cygwin environment, will be able to use the VPN.
-It will also support all features.
-
-@c ==================================================================
-@node MinGW (Windows) build environment
-@subsection MinGW (Windows) build environment
-
-You will need to install the MinGW environment from @uref{http://www.mingw.org}.
-
-When tinc is compiled using MinGW it runs natively under Windows,
-it is not necessary to keep MinGW installed.
-
-When detaching, tinc will install itself as a service,
-which will be restarted automatically after reboots.
-
-
-@c ==================================================================
-@node System files
-@section System files
-
-Before you can run tinc, you must make sure you have all the needed
-files on your system.
-
-@menu
-* Device files::
-* Other files::
-@end menu
-
-
-@c ==================================================================
-@node Device files
-@subsection Device files
-
-@cindex device files
-Most operating systems nowadays come with the necessary device files by default,
-or they have a mechanism to create them on demand.
-
-If you use Linux and do not have udev installed,
-you may need to create the following device file if it does not exist:
-
-@example
-mknod -m 600 /dev/net/tun c 10 200
-@end example
+This manual will contain information on how to compile the MeshLink library itself,
+as well as how to integrate the MeshLink library into your own applications.
@c ==================================================================
-@node Other files
-@subsection Other files
-
-@subsubheading @file{/etc/networks}
-
-You may add a line to @file{/etc/networks} so that your VPN will get a
-symbolic name. For example:
-
-@example
-myvpn 10.0.0.0
-@end example
-
-@subsubheading @file{/etc/services}
-
-@cindex port numbers
-You may add this line to @file{/etc/services}. The effect is that you
-may supply a @samp{tinc} as a valid port number to some programs. The
-number 655 is registered with the IANA.
-
-@example
-tinc 655/tcp TINC
-tinc 655/udp TINC
-# Ivo Timmermans <ivo@@tinc-vpn.org>
-@end example
-
-
-@c
-@c
-@c
-@c
-@c Configuring tinc
-@c
-@c
-@c
-@c
-
+@node About us
+@chapter About us
-@c ==================================================================
-@node Configuration
-@chapter Configuration
@menu
-* Configuration introduction::
-* Multiple networks::
-* How connections work::
-* Configuration files::
-* Network interfaces::
-* Example configuration::
+* Contact information::
+* Authors::
@end menu
-@c ==================================================================
-@node Configuration introduction
-@section Configuration introduction
-
-Before actually starting to configure tinc and editing files,
-make sure you have read this entire section so you know what to expect.
-Then, make it clear to yourself how you want to organize your VPN:
-What are the nodes (computers running tinc)?
-What IP addresses/subnets do they have?
-What is the network mask of the entire VPN?
-Do you need special firewall rules?
-Do you have to set up masquerading or forwarding rules?
-Do you want to run tinc in router mode or switch mode?
-These questions can only be answered by yourself,
-you will not find the answers in this documentation.
-Make sure you have an adequate understanding of networks in general.
-@cindex Network Administrators Guide
-A good resource on networking is the
-@uref{http://www.tldp.org/LDP/nag2/, Linux Network Administrators Guide}.
-
-If you have everything clearly pictured in your mind,
-proceed in the following order:
-First, create the initial configuration files and public/private keypairs using the following command:
-@example
-tinc -n @var{NETNAME} init @var{NAME}
-@end example
-Second, use @samp{tinc -n @var{NETNAME} add ...} to further configure tinc.
-Finally, export your host configuration file using @samp{tinc -n @var{NETNAME} export} and send it to those
-people or computers you want tinc to connect to.
-They should send you their host configuration file back, which you can import using @samp{tinc -n @var{NETNAME} import}.
-
-These steps are described in the subsections below.
-
-
-@c ==================================================================
-@node Multiple networks
-@section Multiple networks
-
-@cindex multiple networks
-@cindex netname
-
-In order to allow you to run more than one tinc daemon on one computer,
-for instance if your computer is part of more than one VPN,
-you can assign a @var{netname} to your VPN.
-It is not required if you only run one tinc daemon,
-it doesn't even have to be the same on all the nodes of your VPN,
-but it is recommended that you choose one anyway.
-
-We will asume you use a netname throughout this document.
-This means that you call tinc with the -n argument,
-which will specify the netname.
-
-The effect of this option is that tinc will set its configuration
-root to @file{@value{sysconfdir}/tinc/@var{netname}/}, where @var{netname} is your argument to the -n option.
-You will also notice that log messages it appears in syslog as coming from @file{tinc.@var{netname}},
-and on Linux, unless specified otherwise, the name of the virtual network interface will be the same as the network name.
-
-However, it is not strictly necessary that you call tinc with the -n
-option. If you don not use it, the network name will just be empty, and
-tinc will look for files in @file{@value{sysconfdir}/tinc/} instead of
-@file{@value{sysconfdir}/tinc/@var{netname}/};
-the configuration file will then be @file{@value{sysconfdir}/tinc/tinc.conf},
-and the host configuration files are expected to be in @file{@value{sysconfdir}/tinc/hosts/}.
-
-
-@c ==================================================================
-@node How connections work
-@section How connections work
-
-When tinc starts up, it parses the command-line options and then
-reads in the configuration file tinc.conf.
-If it sees one or more `ConnectTo' values pointing to other tinc daemons in that file,
-it will try to connect to those other daemons.
-Whether this succeeds or not and whether `ConnectTo' is specified or not,
-tinc will listen for incoming connection from other deamons.
-If you did specify a `ConnectTo' value and the other side is not responding,
-tinc will keep retrying.
-This means that once started, tinc will stay running until you tell it to stop,
-and failures to connect to other tinc daemons will not stop your tinc daemon
-for trying again later.
-This means you don't have to intervene if there are temporary network problems.
-
-@cindex client
-@cindex server
-There is no real distinction between a server and a client in tinc.
-If you wish, you can view a tinc daemon without a `ConnectTo' value as a server,
-and one which does specify such a value as a client.
-It does not matter if two tinc daemons have a `ConnectTo' value pointing to each other however.
-
-Connections specified using `ConnectTo' are so-called meta-connections.
-Tinc daemons exchange information about all other daemon they know about via these meta-connections.
-After learning about all the daemons in the VPN,
-tinc will create other connections as necessary in order to communicate with them.
-For example, if there are three daemons named A, B and C, and A has @samp{ConnectTo = B} in its tinc.conf file,
-and C has @samp{ConnectTo = B} in its tinc.conf file, then A will learn about C from B,
-and will be able to exchange VPN packets with C without the need to have @samp{ConnectTo = C} in its tinc.conf file.
-
-It could be that some daemons are located behind a Network Address Translation (NAT) device, or behind a firewall.
-In the above scenario with three daemons, if A and C are behind a NAT,
-B will automatically help A and C punch holes through their NAT,
-in a way similar to the STUN protocol, so that A and C can still communicate with each other directly.
-It is not always possible to do this however, and firewalls might also prevent direct communication.
-In that case, VPN packets between A and C will be forwarded by B.
-
-In effect, all nodes in the VPN will be able to talk to each other, as long as
-their is a path of meta-connections between them, and whenever possible, two
-nodes will communicate with each other directly.
-
@c ==================================================================
-@node Configuration files
-@section Configuration files
-
-The actual configuration of the daemon is done in the file
-@file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf} and at least one other file in the directory
-@file{@value{sysconfdir}/tinc/@var{netname}/hosts/}.
-
-An optionnal directory @file{@value{sysconfdir}/tinc/@var{netname}/conf.d} can be added from which
-any .conf file will be read.
-
-These file consists of comments (lines started with a #) or assignments
-in the form of
-
-@example
-Variable = Value.
-@end example
-
-The variable names are case insensitive, and any spaces, tabs, newlines
-and carriage returns are ignored. Note: it is not required that you put
-in the `=' sign, but doing so improves readability. If you leave it
-out, remember to replace it with at least one space character.
-
-The server configuration is complemented with host specific configuration (see
-the next section). Although all host configuration options for the local node
-listed in this document can also be put in
-@file{@value{sysconfdir}/tinc/@var{netname}/tinc.conf}, it is recommended to
-put host specific configuration options in the host configuration file, as this
-makes it easy to exchange with other nodes.
-
-You can edit the config file manually, but it is recommended that you use
-the tinc command to change configuration variables for you.
-
-In the following two subsections all valid variables are listed in alphabetical order.
-The default value is given between parentheses,
-other comments are between square brackets.
+@node Contact information
+@section Contact information
-@menu
-* Main configuration variables::
-* Host configuration variables::
-* Scripts::
-* How to configure::
-@end menu
+The MeshLink website is at @url{http://meshlink.io/}.
@c ==================================================================
-@node Main configuration variables
-@subsection Main configuration variables
-
-@table @asis
-@cindex AddressFamily
-@item AddressFamily = <ipv4|ipv6|any> (any)
-This option affects the address family of listening and outgoing sockets.
-If any is selected, then depending on the operating system
-both IPv4 and IPv6 or just IPv6 listening sockets will be created.
-
-@cindex AutoConnect
-@item AutoConnect = <count> (0) [experimental]
-If set to a non-zero value,
-tinc will try to only have count meta connections to other nodes,
-by automatically making or breaking connections to known nodes.
-Higher values increase redundancy but also increase meta data overhead.
-When using this option, a good value is 3.
-
-@cindex BindToAddress
-@item BindToAddress = <@var{address}> [<@var{port}>]
-This is the same as ListenAddress, however the address given with the BindToAddress option
-will also be used for outgoing connections.
-This is useful if your computer has more than one IPv4 or IPv6 address,
-and you want tinc to only use a specific one for outgoing packets.
-
-@cindex BindToInterface
-@item BindToInterface = <@var{interface}> [experimental]
-If you have more than one network interface in your computer, tinc will
-by default listen on all of them for incoming connections. It is
-possible to bind tinc to a single interface like eth0 or ppp0 with this
-variable.
-
-This option may not work on all platforms.
-Also, on some platforms it will not actually bind to an interface,
-but rather to the address that the interface has at the moment a socket is created.
-
-@cindex Broadcast
-@item Broadcast = <no | mst | direct> (mst) [experimental]
-This option selects the way broadcast packets are sent to other daemons.
-@emph{NOTE: all nodes in a VPN must use the same Broadcast mode, otherwise routing loops can form.}
-
-@table @asis
-@item no
-Broadcast packets are never sent to other nodes.
-
-@item mst
-Broadcast packets are sent and forwarded via the VPN's Minimum Spanning Tree.
-This ensures broadcast packets reach all nodes.
-
-@item direct
-Broadcast packets are sent directly to all nodes that can be reached directly.
-Broadcast packets received from other nodes are never forwarded.
-If the IndirectData option is also set, broadcast packets will only be sent to nodes which we have a meta connection to.
-@end table
-
-@cindex ConnectTo
-@item ConnectTo = <@var{name}>
-Specifies which other tinc daemon to connect to on startup.
-Multiple ConnectTo variables may be specified,
-in which case outgoing connections to each specified tinc daemon are made.
-The names should be known to this tinc daemon
-(i.e., there should be a host configuration file for the name on the ConnectTo line).
-
-If you don't specify a host with ConnectTo,
-tinc won't try to connect to other daemons at all,
-and will instead just listen for incoming connections.
-
-@cindex DecrementTTL
-@item DecrementTTL = <yes | no> (no) [experimental]
-When enabled, tinc will decrement the Time To Live field in IPv4 packets, or the Hop Limit field in IPv6 packets,
-before forwarding a received packet to the virtual network device or to another node,
-and will drop packets that have a TTL value of zero,
-in which case it will send an ICMP Time Exceeded packet back.
-
-Do not use this option if you use switch mode and want to use IPv6.
-
-@cindex Device
-@item Device = <@var{device}> (@file{/dev/tap0}, @file{/dev/net/tun} or other depending on platform)
-The virtual network device to use.
-Tinc will automatically detect what kind of device it is.
-Note that you can only use one device per daemon.
-Under Windows, use @var{Interface} instead of @var{Device}.
-Note that you can only use one device per daemon.
-See also @ref{Device files}.
-
-@cindex DeviceType
-@item DeviceType = <@var{type}> (platform dependent)
-The type of the virtual network device.
-Tinc will normally automatically select the right type of tun/tap interface, and this option should not be used.
-However, this option can be used to select one of the special interface types, if support for them is compiled in.
-
-@table @asis
-@cindex dummy
-@item dummy
-Use a dummy interface.
-No packets are ever read or written to a virtual network device.
-Useful for testing, or when setting up a node that only forwards packets for other nodes.
-
-@cindex raw_socket
-@item raw_socket
-Open a raw socket, and bind it to a pre-existing
-@var{Interface} (eth0 by default).
-All packets are read from this interface.
-Packets received for the local node are written to the raw socket.
-However, at least on Linux, the operating system does not process IP packets destined for the local host.
-
-@cindex multicast
-@item multicast
-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}.
-Packets are read from and written to this multicast socket.
-This can be used to connect to UML, QEMU or KVM instances listening on the same multicast address.
-Do NOT connect multiple tinc daemons to the same multicast address, this will very likely cause routing loops.
-Also note that this can cause decrypted VPN packets to be sent out on a real network if misconfigured.
-
-@cindex UML
-@item uml (not compiled in by default)
-Create a UNIX socket with the filename specified by
-@var{Device}, or @file{@value{localstatedir}/run/@var{netname}.umlsocket}
-if not specified.
-Tinc will wait for a User Mode Linux instance to connect to this socket.
-
-@cindex VDE
-@item vde (not compiled in by default)
-Uses the libvdeplug library to connect to a Virtual Distributed Ethernet switch,
-using the UNIX socket specified by
-@var{Device}, or @file{@value{localstatedir}/run/vde.ctl}
-if not specified.
-@end table
-
-Also, in case tinc does not seem to correctly interpret packets received from the virtual network device,
-it can be used to change the way packets are interpreted:
+@node Authors
+@section Authors
@table @asis
-@item tun (BSD and Linux)
-Set type to tun.
-Depending on the platform, this can either be with or without an address family header (see below).
-
-@cindex tunnohead
-@item tunnohead (BSD)
-Set type to tun without an address family header.
-Tinc will expect packets read from the virtual network device to start with an IP header.
-On some platforms IPv6 packets cannot be read from or written to the device in this mode.
-
-@cindex tunifhead
-@item tunifhead (BSD)
-Set type to tun with an address family header.
-Tinc will expect packets read from the virtual network device
-to start with a four byte header containing the address family,
-followed by an IP header.
-This mode should support both IPv4 and IPv6 packets.
-
-@item tap (BSD and Linux)
-Set type to tap.
-Tinc will expect packets read from the virtual network device
-to start with an Ethernet header.
+@item Guus Sliepen (@email{guus@@meshlink.io})
@end table
-@cindex DirectOnly
-@item DirectOnly = <yes|no> (no) [experimental]
-When this option is enabled, packets that cannot be sent directly to the destination node,
-but which would have to be forwarded by an intermediate node, are dropped instead.
-When combined with the IndirectData option,
-packets for nodes for which we do not have a meta connection with are also dropped.
-
-@cindex ECDSAPrivateKeyFile
-@item ECDSAPrivateKeyFile = <@var{path}> (@file{@value{sysconfdir}/tinc/@var{netname}/ecdsa_key.priv})
-The file in which the private ECDSA key of this tinc daemon resides.
-This is only used if ExperimentalProtocol is enabled.
-
-@cindex ExperimentalProtocol
-@item ExperimentalProtocol = <yes|no> (yes)
-When this option is enabled, the SPTPS protocol will be used when connecting to nodes that also support it.
-Ephemeral ECDH will be used for key exchanges,
-and ECDSA will be used instead of RSA for authentication.
-When enabled, an ECDSA key must have been generated before with
-@samp{tinc generate-ecdsa-keys}.
-
-@cindex Forwarding
-@item Forwarding = <off|internal|kernel> (internal) [experimental]
-This option selects the way indirect packets are forwarded.
-
-@table @asis
-@item off
-Incoming packets that are not meant for the local node,
-but which should be forwarded to another node, are dropped.
-
-@item internal
-Incoming packets that are meant for another node are forwarded by tinc internally.
-
-This is the default mode, and unless you really know you need another forwarding mode, don't change it.
-
-@item kernel
-Incoming packets are always sent to the TUN/TAP device, even if the packets are not for the local node.
-This is less efficient, but allows the kernel to apply its routing and firewall rules on them,
-and can also help debugging.
-@end table
-
-@cindex Hostnames
-@item Hostnames = <yes|no> (no)
-This option selects whether IP addresses (both real and on the VPN)
-should be resolved. Since DNS lookups are blocking, it might affect
-tinc's efficiency, even stopping the daemon for a few seconds everytime
-it does a lookup if your DNS server is not responding.
-
-This does not affect resolving hostnames to IP addresses from the
-configuration file, but whether hostnames should be resolved while logging.
-
-@cindex Interface
-@item Interface = <@var{interface}>
-Defines the name of the interface corresponding to the virtual network device.
-Depending on the operating system and the type of device this may or may not actually set the name of the interface.
-Under Windows, this variable is used to select which network interface will be used.
-If you specified a Device, this variable is almost always already correctly set.
-
-@cindex ListenAddress
-@item ListenAddress = <@var{address}> [<@var{port}>]
-If your computer has more than one IPv4 or IPv6 address, tinc
-will by default listen on all of them for incoming connections.
-This option can be used to restrict which addresses tinc listens on.
-Multiple ListenAddress variables may be specified,
-in which case listening sockets for each specified address are made.
-
-If no @var{port} is specified, the socket will listen on the port specified by the Port option,
-or to port 655 if neither is given.
-To only listen on a specific port but not to a specific address, use "*" for the @var{address}.
-
-@cindex LocalDiscovery
-@item LocalDiscovery = <yes | no> (no)
-When enabled, tinc will try to detect peers that are on the same local network.
-This will allow direct communication using LAN addresses, even if both peers are behind a NAT
-and they only ConnectTo a third node outside the NAT,
-which normally would prevent the peers from learning each other's LAN address.
-
-Currently, local discovery is implemented by sending broadcast packets to the LAN during path MTU discovery.
-This feature may not work in all possible situations.
-
-@cindex LocalDiscoveryAddress
-@item LocalDiscoveryAddress <@var{address}>
-If this variable is specified, local discovery packets are sent to the given @var{address}.
-
-@cindex Mode
-@item Mode = <router|switch|hub> (router)
-This option selects the way packets are routed to other daemons.
-
-@table @asis
-@cindex router
-@item router
-In this mode Subnet
-variables in the host configuration files will be used to form a routing table.
-Only packets of routable protocols (IPv4 and IPv6) are supported in this mode.
-
-This is the default mode, and unless you really know you need another mode, don't change it.
-
-@cindex switch
-@item switch
-In this mode the MAC addresses of the packets on the VPN will be used to
-dynamically create a routing table just like an Ethernet switch does.
-Unicast, multicast and broadcast packets of every protocol that runs over Ethernet are supported in this mode
-at the cost of frequent broadcast ARP requests and routing table updates.
-
-This mode is primarily useful if you want to bridge Ethernet segments.
-
-@cindex hub
-@item hub
-This mode is almost the same as the switch mode, but instead
-every packet will be broadcast to the other daemons
-while no routing table is managed.
-@end table
-
-@cindex KeyExpire
-@item KeyExpire = <@var{seconds}> (3600)
-This option controls the time the encryption keys used to encrypt the data
-are valid. It is common practice to change keys at regular intervals to
-make it even harder for crackers, even though it is thought to be nearly
-impossible to crack a single key.
-
-@cindex MACExpire
-@item MACExpire = <@var{seconds}> (600)
-This option controls the amount of time MAC addresses are kept before they are removed.
-This only has effect when Mode is set to "switch".
-
-@cindex MaxConnectionBurst
-@item MaxConnectionBurst = <@var{count}> (100)
-This option controls how many connections tinc accepts in quick succession.
-If there are more connections than the given number in a short time interval,
-tinc will reduce the number of accepted connections to only one per second,
-until the burst has passed.
-
-@cindex Name
-@item Name = <@var{name}> [required]
-This is a symbolic name for this connection.
-The name should consist only of alfanumeric and underscore characters (a-z, A-Z, 0-9 and _), and is case sensitive.
-
-If Name starts with a $, then the contents of the environment variable that follows will be used.
-In that case, invalid characters will be converted to underscores.
-If Name is $HOST, but no such environment variable exist,
-the hostname will be read using the gethostname() system call.
-
-@cindex PingInterval
-@item PingInterval = <@var{seconds}> (60)
-The number of seconds of inactivity that tinc will wait before sending a
-probe to the other end.
-
-@cindex PingTimeout
-@item PingTimeout = <@var{seconds}> (5)
-The number of seconds to wait for a response to pings or to allow meta
-connections to block. If the other end doesn't respond within this time,
-the connection is terminated, and the others will be notified of this.
-
-@cindex PriorityInheritance
-@item PriorityInheritance = <yes|no> (no) [experimental]
-When this option is enabled the value of the TOS field of tunneled IPv4 packets
-will be inherited by the UDP packets that are sent out.
-
-@cindex PrivateKey
-@item PrivateKey = <@var{key}> [obsolete]
-This is the RSA private key for tinc. However, for safety reasons it is
-advised to store private keys of any kind in separate files. This prevents
-accidental eavesdropping if you are editting the configuration file.
-
-@cindex PrivateKeyFile
-@item PrivateKeyFile = <@var{path}> (@file{@value{sysconfdir}/tinc/@var{netname}/rsa_key.priv})
-This is the full path name of the RSA private key file that was
-generated by @samp{tinc generate-keys}. It must be a full path, not a
-relative directory.
-
-@cindex ProcessPriority
-@item ProcessPriority = <low|normal|high>
-When this option is used the priority of the tincd process will be adjusted.
-Increasing the priority may help to reduce latency and packet loss on the VPN.
-
-@cindex Proxy
-@item Proxy = socks4 | socks5 | http | exec @var{...} [experimental]
-Use a proxy when making outgoing connections.
-The following proxy types are currently supported:
-
-@table @asis
-@cindex socks4
-@item socks4 <@var{address}> <@var{port}> [<@var{username}>]
-Connects to the proxy using the SOCKS version 4 protocol.
-Optionally, a @var{username} can be supplied which will be passed on to the proxy server.
-
-@cindex socks5
-@item socks5 <@var{address}> <@var{port}> [<@var{username}> <@var{password}>]
-Connect to the proxy using the SOCKS version 5 protocol.
-If a @var{username} and @var{password} are given, basic username/password authentication will be used,
-otherwise no authentication will be used.
-
-@cindex http
-@item http <@var{address}> <@var{port}>
-Connects to the proxy and sends a HTTP CONNECT request.
-
-@cindex exec
-@item exec <@var{command}>
-Executes the given command which should set up the outgoing connection.
-The environment variables @env{NAME}, @env{NODE}, @env{REMOTEADDRES} and @env{REMOTEPORT} are available.
-@end table
-
-@cindex ReplayWindow
-@item ReplayWindow = <bytes> (16)
-This is the size of the replay tracking window for each remote node, in bytes.
-The window is a bitfield which tracks 1 packet per bit, so for example
-the default setting of 16 will track up to 128 packets in the window. In high
-bandwidth scenarios, setting this to a higher value can reduce packet loss from
-the interaction of replay tracking with underlying real packet loss and/or
-reordering. Setting this to zero will disable replay tracking completely and
-pass all traffic, but leaves tinc vulnerable to replay-based attacks on your
-traffic.
-
-@cindex StrictSubnets
-@item StrictSubnets = <yes|no> (no) [experimental]
-When this option is enabled tinc will only use Subnet statements which are
-present in the host config files in the local
-@file{@value{sysconfdir}/tinc/@var{netname}/hosts/} directory.
-Subnets learned via connections to other nodes and which are not
-present in the local host config files are ignored.
-
-@cindex TunnelServer
-@item TunnelServer = <yes|no> (no) [experimental]
-When this option is enabled tinc will no longer forward information between other tinc daemons,
-and will only allow connections with nodes for which host config files are present in the local
-@file{@value{sysconfdir}/tinc/@var{netname}/hosts/} directory.
-Setting this options also implicitly sets StrictSubnets.
-
-@cindex UDPRcvBuf
-@item UDPRcvBuf = <bytes> (OS default)
-Sets the socket receive buffer size for the UDP socket, in bytes.
-If unset, the default buffer size will be used by the operating system.
-
-@cindex UDPSndBuf
-@item UDPSndBuf = <bytes> Pq OS default
-Sets the socket send buffer size for the UDP socket, in bytes.
-If unset, the default buffer size will be used by the operating system.
-
-@end table
-
-
-@c ==================================================================
-@node Host configuration variables
-@subsection Host configuration variables
-
-@table @asis
-@cindex Address
-@item Address = <@var{IP address}|@var{hostname}> [<port>] [recommended]
-This variable is only required if you want to connect to this host. It
-must resolve to the external IP address where the host can be reached,
-not the one that is internal to the VPN.
-If no port is specified, the default Port is used.
-Multiple Address variables can be specified, in which case each address will be
-tried until a working connection has been established.
-
-@cindex Cipher
-@item Cipher = <@var{cipher}> (blowfish)
-The symmetric cipher algorithm used to encrypt UDP packets using the legacy protocol.
-Any cipher supported by OpenSSL is recognized.
-Furthermore, specifying "none" will turn off packet encryption.
-It is best to use only those ciphers which support CBC mode.
-This option has no effect for connections using the SPTPS protocol, which always use AES-256-CTR.
-
-@cindex ClampMSS
-@item ClampMSS = <yes|no> (yes)
-This option specifies whether tinc should clamp the maximum segment size (MSS)
-of TCP packets to the path MTU. This helps in situations where ICMP
-Fragmentation Needed or Packet too Big messages are dropped by firewalls.
-
-@cindex Compression
-@item Compression = <@var{level}> (0)
-This option sets the level of compression used for UDP packets.
-Possible values are 0 (off), 1 (fast zlib) and any integer up to 9 (best zlib),
-10 (fast lzo) and 11 (best lzo).
-
-@cindex Digest
-@item Digest = <@var{digest}> (sha1)
-The digest algorithm used to authenticate UDP packets using the legacy protocol.
-Any digest supported by OpenSSL is recognized.
-Furthermore, specifying "none" will turn off packet authentication.
-This option has no effect for connections using the SPTPS protocol, which always use HMAC-SHA-256.
-
-@cindex IndirectData
-@item IndirectData = <yes|no> (no)
-When set to yes, other nodes which do not already have a meta connection to you
-will not try to establish direct communication with you.
-It is best to leave this option out or set it to no.
-
-@cindex MACLength
-@item MACLength = <@var{bytes}> (4)
-The length of the message authentication code used to authenticate UDP packets using the legacy protocol.
-Can be anything from 0
-up to the length of the digest produced by the digest algorithm.
-This option has no effect for connections using the SPTPS protocol, which never truncate MACs.
-
-@cindex PMTU
-@item PMTU = <@var{mtu}> (1514)
-This option controls the initial path MTU to this node.
-
-@cindex PMTUDiscovery
-@item PMTUDiscovery = <yes|no> (yes)
-When this option is enabled, tinc will try to discover the path MTU to this node.
-After the path MTU has been discovered, it will be enforced on the VPN.
-
-@cindex Port
-@item Port = <@var{port}> (655)
-This is the port this tinc daemon listens on.
-You can use decimal portnumbers or symbolic names (as listed in @file{/etc/services}).
-
-@cindex PublicKey
-@item PublicKey = <@var{key}> [obsolete]
-This is the RSA public key for this host.
-
-@cindex PublicKeyFile
-@item PublicKeyFile = <@var{path}> [obsolete]
-This is the full path name of the RSA public key file that was generated
-by @samp{tinc generate-keys}. It must be a full path, not a relative
-directory.
-
-@cindex PEM format
-From version 1.0pre4 on tinc will store the public key directly into the
-host configuration file in PEM format, the above two options then are not
-necessary. Either the PEM format is used, or exactly
-@strong{one of the above two options} must be specified
-in each host configuration file, if you want to be able to establish a
-connection with that host.
-
-@cindex Subnet
-@item Subnet = <@var{address}[/@var{prefixlength}[#@var{weight}]]>
-The subnet which this tinc daemon will serve.
-Tinc tries to look up which other daemon it should send a packet to by searching the appropiate subnet.
-If the packet matches a subnet,
-it will be sent to the daemon who has this subnet in his host configuration file.
-Multiple subnet lines can be specified for each daemon.
-
-Subnets can either be single MAC, IPv4 or IPv6 addresses,
-in which case a subnet consisting of only that single address is assumed,
-or they can be a IPv4 or IPv6 network address with a prefixlength.
-For example, IPv4 subnets must be in a form like 192.168.1.0/24,
-where 192.168.1.0 is the network address and 24 is the number of bits set in the netmask.
-Note that subnets like 192.168.1.1/24 are invalid!
-Read a networking HOWTO/FAQ/guide if you don't understand this.
-IPv6 subnets are notated like fec0:0:0:1::/64.
-MAC addresses are notated like 0:1a:2b:3c:4d:5e.
-
-@cindex CIDR notation
-Prefixlength is the number of bits set to 1 in the netmask part; for
-example: netmask 255.255.255.0 would become /24, 255.255.252.0 becomes
-/22. This conforms to standard CIDR notation as described in
-@uref{http://www.ietf.org/rfc/rfc1519.txt, RFC1519}
-
-A Subnet can be given a weight to indicate its priority over identical Subnets
-owned by different nodes. The default weight is 10. Lower values indicate
-higher priority. Packets will be sent to the node with the highest priority,
-unless that node is not reachable, in which case the node with the next highest
-priority will be tried, and so on.
-
-@cindex TCPonly
-@item TCPonly = <yes|no> (no)
-If this variable is set to yes, then the packets are tunnelled over a
-TCP connection instead of a UDP connection. This is especially useful
-for those who want to run a tinc daemon from behind a masquerading
-firewall, or if UDP packet routing is disabled somehow.
-Setting this options also implicitly sets IndirectData.
-
-@cindex Weight
-@item Weight = <weight>
-If this variable is set, it overrides the weight given to connections made with
-another host. A higher weight means a lower priority is given to this
-connection when broadcasting or forwarding packets.
-@end table
-
-
-@c ==================================================================
-@node Scripts
-@subsection Scripts
-
-@cindex scripts
-Apart from reading the server and host configuration files,
-tinc can also run scripts at certain moments.
-Under Windows (not Cygwin), the scripts should have the extension @file{.bat} or @file{.cmd}.
-
-@table @file
-@cindex tinc-up
-@item @value{sysconfdir}/tinc/@var{netname}/tinc-up
-This is the most important script.
-If it is present it will be executed right after the tinc daemon has been
-started and has connected to the virtual network device.
-It should be used to set up the corresponding network interface,
-but can also be used to start other things.
-Under Windows you can use the Network Connections control panel instead of creating this script.
-
-@cindex tinc-down
-@item @value{sysconfdir}/tinc/@var{netname}/tinc-down
-This script is started right before the tinc daemon quits.
-
-@item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-up
-This script is started when the tinc daemon with name @var{host} becomes reachable.
-
-@item @value{sysconfdir}/tinc/@var{netname}/hosts/@var{host}-down
-This script is started when the tinc daemon with name @var{host} becomes unreachable.
-
-@item @value{sysconfdir}/tinc/@var{netname}/host-up
-This script is started when any host becomes reachable.
-
-@item @value{sysconfdir}/tinc/@var{netname}/host-down
-This script is started when any host becomes unreachable.
-
-@item @value{sysconfdir}/tinc/@var{netname}/subnet-up
-This script is started when a Subnet becomes reachable.
-The Subnet and the node it belongs to are passed in environment variables.
-
-@item @value{sysconfdir}/tinc/@var{netname}/subnet-down
-This script is started when a Subnet becomes unreachable.
-
-@item @value{sysconfdir}/tinc/@var{netname}/invitation-created
-This script is started when a new invitation has been created.
-
-@item @value{sysconfdir}/tinc/@var{netname}/invitation-accepted
-This script is started when an invitation has been used.
-
-@end table
-
-@cindex environment variables
-The scripts are started without command line arguments,
-but can make use of certain environment variables.
-Under UNIX like operating systems the names of environment variables must be preceded by a $ in scripts.
-Under Windows, in @file{.bat} or @file{.cmd} files, they have to be put between % signs.
-
-@table @env
-@cindex NETNAME
-@item NETNAME
-If a netname was specified, this environment variable contains it.
-
-@cindex NAME
-@item NAME
-Contains the name of this tinc daemon.
-
-@cindex DEVICE
-@item DEVICE
-Contains the name of the virtual network device that tinc uses.
-
-@cindex INTERFACE
-@item INTERFACE
-Contains the name of the virtual network interface that tinc uses.
-This should be used for commands like ifconfig.
-
-@cindex NODE
-@item NODE
-When a host becomes (un)reachable, this is set to its name.
-If a subnet becomes (un)reachable, this is set to the owner of that subnet.
-
-@cindex REMOTEADDRESS
-@item REMOTEADDRESS
-When a host becomes (un)reachable, this is set to its real address.
-
-@cindex REMOTEPORT
-@item REMOTEPORT
-When a host becomes (un)reachable,
-this is set to the port number it uses for communication with other tinc daemons.
-
-@cindex SUBNET
-@item SUBNET
-When a subnet becomes (un)reachable, this is set to the subnet.
-
-@cindex WEIGHT
-@item WEIGHT
-When a subnet becomes (un)reachable, this is set to the subnet weight.
-
-@cindex INVITATION_FILE
-@item INVITATION_FILE
-When the @file{invitation-created} script is called,
-this is set to the file where the invitation details will be stored.
-
-@cindex INVITATION_URL
-@item INVITATION_URL
-When the @file{invitation-created} script is called,
-this is set to the invitation URL that has been created.
-@end table
-
-Do not forget that under UNIX operating systems,
-you have to make the scripts executable, using the command @samp{chmod a+x script}.
-
-
-@c ==================================================================
-@node How to configure
-@subsection How to configure
-
-@subsubheading Step 1. Creating initial configuration files.
-
-The initial directory structure, configuration files and public/private keypairs are created using the following command:
-
-@example
-tinc -n @var{netname} init @var{name}
-@end example
-
-(You will need to run this as root, or use "sudo".)
-This will create the configuration directory @file{@value{sysconfdir}/tinc/@var{netname}.},
-and inside it will create another directory named @file{hosts/}.
-In the configuration directory, it will create the file @file{tinc.conf} with the following contents:
-
-@example
-Name = @var{name}
-@end example
-
-It will also create private RSA and ECDSA keys, which will be stored in the files @file{rsa_key.priv} and @file{ecdsa_key.priv}.
-It will also create a host configuration file @file{hosts/@var{name}},
-which will contain the corresponding public RSA and ECDSA keys.
-
-Finally, on UNIX operating systems, it will create an executable script @file{tinc-up},
-which will initially not do anything except warning that you should edit it.
-
-@subsubheading Step 2. Modifying the initial configuration.
-
-Unless you want to use tinc in switch mode,
-you should now configure which range of addresses you will use on the VPN.
-Let's assume you will be part of a VPN which uses the address range 192.168.0.0/16,
-and you yourself have a smaller portion of that range: 192.168.2.0/24.
-Then you should run the following command:
-
-@example
-tinc -n @var{netname} add subnet 192.168.2.0/24
-@end example
-
-This will add a Subnet statement to your host configuration file.
-Try opening the file @file{@value{sysconfdir}/tinc/@var{netname}/hosts/@var{name}} in an editor.
-You should now see a file containing the public RSA and ECDSA keys (which looks like a bunch of random characters),
-and the following line at the bottom:
-
-@example
-Subnet = 192.168.2.0/24
-@end example
-
-If you will use more than one address range, you can add more Subnets.
-For example, if you also use the IPv6 subnet fec0:0:0:2::/64, you can add it as well:
-
-@example
-tinc -n @var{netname} add subnet fec0:0:0:2::/24
-@end example
-
-This will add another line to the file @file{hosts/@var{name}}.
-If you make a mistake, you can undo it by simply using @samp{del} instead of @samp{add}.
-
-If you want other tinc daemons to create meta-connections to your daemon,
-you should add your public IP address or hostname to your host configuration file.
-For example, if your hostname is foo.example.org, run:
-
-@example
-tinc -n @var{netname} add address foo.example.org
-@end example
-
-If you already know to which daemons your daemon should make meta-connections,
-you should configure that now as well.
-Suppose you want to connect to a daemon named "bar", run:
-
-@example
-tinc -n @var{netname} add connectto bar
-@end example
-
-Note that you specify the Name of the other daemon here, not an IP address or hostname!
-When you start tinc, and it tries to make a connection to "bar",
-it will look for a host configuration file named @file{hosts/bar},
-and will read Address statements and public keys from that file.
-
-@subsubheading Step 2. Exchanging configuration files.
-
-If your daemon has a ConnectTo = bar statement in its @file{tinc.conf} file,
-or if bar has a ConnectTo your daemon, then you both need each other's host configuration files.
-You should send @file{hosts/@var{name}} to bar, and bar should send you his file which you should move to @file{hosts/bar}.
-If you are on a UNIX platform, you can easily send an email containing the necessary information using the following command
-(assuming the owner of bar has the email address bar@@example.org):
-
-@example
-tinc -n @var{netname} export | mail -s "My config file" bar@@example.org
-@end example
-
-If the owner of bar does the same to send his host configuration file to you,
-you can probably pipe his email through the following command,
-or you can just start this command in a terminal and copy&paste the email:
-
-@example
-tinc -n @var{netname} import
-@end example
-
-If you are the owner of bar yourself, and you have SSH access to that computer,
-you can also swap the host configuration files using the following command:
-
-@example
-tinc -n @var{netname} export \
- | ssh bar.example.org tinc -n @var{netname} exchange \
- | tinc -n @var{netname} import
-@end example
-
-You should repeat this for all nodes you ConnectTo, or which ConnectTo you.
-However, remember that you do not need to ConnectTo all nodes in the VPN;
-it is only necessary to create one or a few meta-connections,
-after the connections are made tinc will learn about all the other nodes in the VPN,
-and will automatically make other connections as necessary.
-
-
-@c ==================================================================
-@node Network interfaces
-@section Network interfaces
-
-Before tinc can start transmitting data over the tunnel, it must
-set up the virtual network interface.
-
-First, decide which IP addresses you want to have associated with these
-devices, and what network mask they must have.
-
-Tinc will open a virtual network device (@file{/dev/tun}, @file{/dev/tap0} or similar),
-which will also create a network interface called something like @samp{tun0}, @samp{tap0}.
-If you are using the Linux tun/tap driver, the network interface will by default have the same name as the @var{netname}.
-Under Windows you can change the name of the network interface from the Network Connections control panel.
-
-@cindex tinc-up
-You can configure the network interface by putting ordinary ifconfig, route, and other commands
-to a script named @file{@value{sysconfdir}/tinc/@var{netname}/tinc-up}.
-When tinc starts, this script will be executed. When tinc exits, it will execute the script named
-@file{@value{sysconfdir}/tinc/@var{netname}/tinc-down}, but normally you don't need to create that script.
-You can manually open the script in an editor, or use the following command:
-
-@example
-tinc -n @var{netname} edit tinc-up
-@end example
-
-An example @file{tinc-up} script, that would be appropriate for the scenario in the previous section, is:
-
-@example
-#!/bin/sh
-ifconfig $INTERFACE 192.168.2.1 netmask 255.255.0.0
-ip addr add fec0:0:0:2::/48 dev $INTERFACE
-@end example
-
-The first command gives the interface an IPv4 address and a netmask.
-The kernel will also automatically add an IPv4 route to this interface, so normally you don't need
-to add route commands to the @file{tinc-up} script.
-The kernel will also bring the interface up after this command.
-@cindex netmask
-The netmask is the mask of the @emph{entire} VPN network, not just your
-own subnet.
-The second command gives the interface an IPv6 address and netmask,
-which will also automatically add an IPv6 route.
-If you only want to use "ip addr" commands on Linux, don't forget that it doesn't bring the interface up, unlike ifconfig,
-so you need to add @samp{ip link set $INTERFACE up} in that case.
-
-The exact syntax of the ifconfig and route commands differs from platform to platform.
-You can look up the commands for setting addresses and adding routes in @ref{Platform specific information},
-but it is best to consult the manpages of those utilities on your platform.
-
-
-@c ==================================================================
-@node Example configuration
-@section Example configuration
-
-
-@cindex example
-Imagine the following situation. Branch A of our example `company' wants to connect
-three branch offices in B, C and D using the Internet. All four offices
-have a 24/7 connection to the Internet.
-
-A is going to serve as the center of the network. B and C will connect
-to A, and D will connect to C. Each office will be assigned their own IP
-network, 10.x.0.0.
-
-@example
-A: net 10.1.0.0 mask 255.255.0.0 gateway 10.1.54.1 internet IP 1.2.3.4
-B: net 10.2.0.0 mask 255.255.0.0 gateway 10.2.1.12 internet IP 2.3.4.5
-C: net 10.3.0.0 mask 255.255.0.0 gateway 10.3.69.254 internet IP 3.4.5.6
-D: net 10.4.0.0 mask 255.255.0.0 gateway 10.4.3.32 internet IP 4.5.6.7
-@end example
-
-Here, ``gateway'' is the VPN IP address of the machine that is running the
-tincd, and ``internet IP'' is the IP address of the firewall, which does not
-need to run tincd, but it must do a port forwarding of TCP and UDP on port
-655 (unless otherwise configured).
-
-In this example, it is assumed that eth0 is the interface that points to
-the inner (physical) LAN of the office, although this could also be the
-same as the interface that leads to the Internet. The configuration of
-the real interface is also shown as a comment, to give you an idea of
-how these example host is set up. All branches use the netname `company'
-for this particular VPN.
-
-Each branch is set up using the @samp{tinc init} and @samp{tinc config} commands,
-here we just show the end results:
-
-@subsubheading For Branch A
-
-@emph{BranchA} would be configured like this:
-
-In @file{@value{sysconfdir}/tinc/company/tinc-up}:
-
-@example
-#!/bin/sh
-
-# Real interface of internal network:
-# ifconfig eth0 10.1.54.1 netmask 255.255.0.0
-
-ifconfig $INTERFACE 10.1.54.1 netmask 255.0.0.0
-@end example
-
-and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
-
-@example
-Name = BranchA
-@end example
-
-On all hosts, @file{@value{sysconfdir}/tinc/company/hosts/BranchA} contains:
-
-@example
-Subnet = 10.1.0.0/16
-Address = 1.2.3.4
-
------BEGIN RSA PUBLIC KEY-----
-...
------END RSA PUBLIC KEY-----
-@end example
-
-Note that the IP addresses of eth0 and the VPN interface are the same.
-This is quite possible, if you make sure that the netmasks of the interfaces are different.
-It is in fact recommended to give both real internal network interfaces and VPN interfaces the same IP address,
-since that will make things a lot easier to remember and set up.
-
-
-@subsubheading For Branch B
-
-In @file{@value{sysconfdir}/tinc/company/tinc-up}:
-
-@example
-#!/bin/sh
-
-# Real interface of internal network:
-# ifconfig eth0 10.2.43.8 netmask 255.255.0.0
-
-ifconfig $INTERFACE 10.2.1.12 netmask 255.0.0.0
-@end example
-
-and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
-
-@example
-Name = BranchB
-ConnectTo = BranchA
-@end example
-
-Note here that the internal address (on eth0) doesn't have to be the
-same as on the VPN interface. Also, ConnectTo is given so that this node will
-always try to connect to BranchA.
-
-On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchB}:
-
-@example
-Subnet = 10.2.0.0/16
-Address = 2.3.4.5
-
------BEGIN RSA PUBLIC KEY-----
-...
------END RSA PUBLIC KEY-----
-@end example
-
-
-@subsubheading For Branch C
-
-In @file{@value{sysconfdir}/tinc/company/tinc-up}:
-
-@example
-#!/bin/sh
-
-# Real interface of internal network:
-# ifconfig eth0 10.3.69.254 netmask 255.255.0.0
-
-ifconfig $INTERFACE 10.3.69.254 netmask 255.0.0.0
-@end example
-
-and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
-
-@example
-Name = BranchC
-ConnectTo = BranchA
-@end example
-
-C already has another daemon that runs on port 655, so they have to
-reserve another port for tinc. It knows the portnumber it has to listen on
-from it's own host configuration file.
-
-On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchC}:
-
-@example
-Address = 3.4.5.6
-Subnet = 10.3.0.0/16
-Port = 2000
-
------BEGIN RSA PUBLIC KEY-----
-...
------END RSA PUBLIC KEY-----
-@end example
-
-
-@subsubheading For Branch D
-
-In @file{@value{sysconfdir}/tinc/company/tinc-up}:
-
-@example
-#!/bin/sh
-
-# Real interface of internal network:
-# ifconfig eth0 10.4.3.32 netmask 255.255.0.0
-
-ifconfig $INTERFACE 10.4.3.32 netmask 255.0.0.0
-@end example
-
-and in @file{@value{sysconfdir}/tinc/company/tinc.conf}:
-
-@example
-Name = BranchD
-ConnectTo = BranchC
-@end example
-
-D will be connecting to C, which has a tincd running for this network on
-port 2000. It knows the port number from the host configuration file.
-
-On all hosts, in @file{@value{sysconfdir}/tinc/company/hosts/BranchD}:
-
-@example
-Subnet = 10.4.0.0/16
-Address = 4.5.6.7
-
------BEGIN RSA PUBLIC KEY-----
-...
------END RSA PUBLIC KEY-----
-@end example
-
-@subsubheading Key files
-
-A, B, C and D all have their own public/private keypairs:
-
-The private RSA key is stored in @file{@value{sysconfdir}/tinc/company/rsa_key.priv},
-the private ECDSA key is stored in @file{@value{sysconfdir}/tinc/company/ecdsa_key.priv},
-and the public RSA and ECDSA keys are put into the host configuration file in the @file{@value{sysconfdir}/tinc/company/hosts/} directory.
-
-@subsubheading Starting
-
-After each branch has finished configuration and they have distributed
-the host configuration files amongst them, they can start their tinc daemons.
-They don't necessarily have to wait for the other branches to have started
-their daemons, tinc will try connecting until they are available.
-
-
-@c ==================================================================
-@node Running tinc
-@chapter Running tinc
-
-If everything else is done, you can start tinc by typing the following command:
-
-@example
-tinc -n @var{netname} start
-@end example
-
-@cindex daemon
-Tinc will detach from the terminal and continue to run in the background like a good daemon.
-If there are any problems however you can try to increase the debug level
-and look in the syslog to find out what the problems are.
-
-@menu
-* Runtime options::
-* Signals::
-* Debug levels::
-* Solving problems::
-* Error messages::
-* Sending bug reports::
-@end menu
-
-
-@c ==================================================================
-@node Runtime options
-@section Runtime options
-
-Besides the settings in the configuration file, tinc also accepts some
-command line options.
-
-@cindex command line
-@cindex runtime options
-@cindex options
-@c from the manpage
-@table @option
-@item -c, --config=@var{path}
-Read configuration options from the directory @var{path}. The default is
-@file{@value{sysconfdir}/tinc/@var{netname}/}.
-
-@item -D, --no-detach
-Don't fork and detach.
-This will also disable the automatic restart mechanism for fatal errors.
-
-@cindex debug level
-@item -d, --debug=@var{level}
-Set debug level to @var{level}. The higher the debug level, the more gets
-logged. Everything goes via syslog.
-
-@item -n, --net=@var{netname}
-Use configuration for net @var{netname}.
-This will let tinc read all configuration files from
-@file{@value{sysconfdir}/tinc/@var{netname}/}.
-Specifying . for @var{netname} is the same as not specifying any @var{netname}.
-@xref{Multiple networks}.
-
-@item --pidfile=@var{filename}
-Store a cookie in @var{filename} which allows tinc to authenticate.
-If unspecified, the default is
-@file{@value{localstatedir}/run/tinc.@var{netname}.pid}.
-
-@item -o, --option=[@var{HOST}.]@var{KEY}=@var{VALUE}
-Without specifying a @var{HOST}, this will set server configuration variable @var{KEY} to @var{VALUE}.
-If specified as @var{HOST}.@var{KEY}=@var{VALUE},
-this will set the host configuration variable @var{KEY} of the host named @var{HOST} to @var{VALUE}.
-This option can be used more than once to specify multiple configuration variables.
-
-@item -L, --mlock
-Lock tinc into main memory.
-This will prevent sensitive data like shared private keys to be written to the system swap files/partitions.
-
-This option is not supported on all platforms.
-
-@item --logfile[=@var{file}]
-Write log entries to a file instead of to the system logging facility.
-If @var{file} is omitted, the default is @file{@value{localstatedir}/log/tinc.@var{netname}.log}.
-
-@item --bypass-security
-Disables encryption and authentication.
-Only useful for debugging.
-
-@item -R, --chroot
-Change process root directory to the directory where the config file is
-located (@file{@value{sysconfdir}/tinc/@var{netname}/} as determined by
--n/--net option or as given by -c/--config option), for added security.
-The chroot is performed after all the initialization is done, after
-writing pid files and opening network sockets.
-
-Note that this option alone does not do any good without -U/--user, below.
-
-Note also that tinc can't run scripts anymore (such as tinc-down or host-up),
-unless it's setup to be runnable inside chroot environment.
-
-This option is not supported on all platforms.
-@item -U, --user=@var{user}
-Switch to the given @var{user} after initialization, at the same time as
-chroot is performed (see --chroot above). With this option tinc drops
-privileges, for added security.
-
-This option is not supported on all platforms.
-
-@item --help
-Display a short reminder of these runtime options and terminate.
-
-@item --version
-Output version information and exit.
-
-@end table
-
-@c ==================================================================
-@node Signals
-@section Signals
-
-@cindex signals
-You can also send the following signals to a running tincd process:
-
-@c from the manpage
-@table @samp
-
-@item ALRM
-Forces tinc to try to connect to all uplinks immediately.
-Usually tinc attempts to do this itself,
-but increases the time it waits between the attempts each time it failed,
-and if tinc didn't succeed to connect to an uplink the first time after it started,
-it defaults to the maximum time of 15 minutes.
-
-@item HUP
-Partially rereads configuration files.
-Connections to hosts whose host config file are removed are closed.
-New outgoing connections specified in @file{tinc.conf} will be made.
-If the --logfile option is used, this will also close and reopen the log file,
-useful when log rotation is used.
-
-@end table
-
-@c ==================================================================
-@node Debug levels
-@section Debug levels
-
-@cindex debug levels
-The tinc daemon can send a lot of messages to the syslog.
-The higher the debug level, the more messages it will log.
-Each level inherits all messages of the previous level:
-
-@c from the manpage
-@table @samp
-
-@item 0
-This will log a message indicating tinc has started along with a version number.
-It will also log any serious error.
-
-@item 1
-This will log all connections that are made with other tinc daemons.
-
-@item 2
-This will log status and error messages from scripts and other tinc daemons.
-
-@item 3
-This will log all requests that are exchanged with other tinc daemons. These include
-authentication, key exchange and connection list updates.
-
-@item 4
-This will log a copy of everything received on the meta socket.
-
-@item 5
-This will log all network traffic over the virtual private network.
-
-@end table
-
-@c ==================================================================
-@node Solving problems
-@section Solving problems
-
-If tinc starts without problems, but if the VPN doesn't work, you will have to find the cause of the problem.
-The first thing to do is to start tinc with a high debug level in the foreground,
-so you can directly see everything tinc logs:
-
-@example
-tincd -n @var{netname} -d5 -D
-@end example
-
-If tinc does not log any error messages, then you might want to check the following things:
-
-@itemize
-@item @file{tinc-up} script
-Does this script contain the right commands?
-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.
-
-@item Subnet
-Does the Subnet (or Subnets) in the host configuration file of this host match the portion of the VPN that belongs to this host?
-
-@item Firewalls and NATs
-Do you have a firewall or a NAT device (a masquerading firewall or perhaps an ADSL router that performs masquerading)?
-If so, check that it allows TCP and UDP traffic on port 655.
-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.
-You can add @samp{TCPOnly = yes} to your host config file to force tinc to only use a single TCP connection,
-this works through most firewalls and NATs.
-
-@end itemize
-
-
-@c ==================================================================
-@node Error messages
-@section Error messages
-
-What follows is a list of the most common error messages you might find in the logs.
-Some of them will only be visible if the debug level is high enough.
-
-@table @samp
-@item Could not open /dev/tap0: No such device
-
-@itemize
-@item You forgot to `modprobe netlink_dev' or `modprobe ethertap'.
-@item You forgot to compile `Netlink device emulation' in the kernel.
-@end itemize
-
-@item Can't write to /dev/net/tun: No such device
-
-@itemize
-@item You forgot to `modprobe tun'.
-@item You forgot to compile `Universal TUN/TAP driver' in the kernel.
-@item The tun device is located somewhere else in @file{/dev/}.
-@end itemize
-
-@item Network address and prefix length do not match!
-
-@itemize
-@item The Subnet field must contain a @emph{network} address, trailing bits should be 0.
-@item If you only want to use one IP address, set the netmask to /32.
-@end itemize
-
-@item Error reading RSA key file `rsa_key.priv': No such file or directory
-
-@itemize
-@item You forgot to create a public/private keypair.
-@item Specify the complete pathname to the private key file with the @samp{PrivateKeyFile} option.
-@end itemize
-
-@item Warning: insecure file permissions for RSA private key file `rsa_key.priv'!
-
-@itemize
-@item The private key file is readable by users other than root.
-Use chmod to correct the file permissions.
-@end itemize
-
-@item Creating metasocket failed: Address family not supported
-
-@itemize
-@item By default tinc tries to create both IPv4 and IPv6 sockets.
-On some platforms this might not be implemented.
-If the logs show @samp{Ready} later on, then at least one metasocket was created,
-and you can ignore this message.
-You can add @samp{AddressFamily = ipv4} to @file{tinc.conf} to prevent this from happening.
-@end itemize
-
-@item Cannot route packet: unknown IPv4 destination 1.2.3.4
-
-@itemize
-@item You try to send traffic to a host on the VPN for which no Subnet is known.
-@item If it is a broadcast address (ending in .255), it probably is a samba server or a Windows host sending broadcast packets.
-You can ignore it.
-@end itemize
-
-@item Cannot route packet: ARP request for unknown address 1.2.3.4
-
-@itemize
-@item You try to send traffic to a host on the VPN for which no Subnet is known.
-@end itemize
-
-@item Packet with destination 1.2.3.4 is looping back to us!
-
-@itemize
-@item Something is not configured right. Packets are being sent out to the
-virtual network device, but according to the Subnet directives in your host configuration
-file, those packets should go to your own host. Most common mistake is that
-you have a Subnet line in your host configuration file with a prefix length which is
-just as large as the prefix of the virtual network interface. The latter should in almost all
-cases be larger. Rethink your configuration.
-Note that you will only see this message if you specified a debug
-level of 5 or higher!
-@item Chances are that a @samp{Subnet = ...} line in the host configuration file of this tinc daemon is wrong.
-Change it to a subnet that is accepted locally by another interface,
-or if that is not the case, try changing the prefix length into /32.
-@end itemize
-
-@item Node foo (1.2.3.4) is not reachable
-
-@itemize
-@item Node foo does not have a connection anymore, its tinc daemon is not running or its connection to the Internet is broken.
-@end itemize
-
-@item Received UDP packet from unknown source 1.2.3.4 (port 12345)
-
-@itemize
-@item If you see this only sporadically, it is harmless and caused by a node sending packets using an old key.
-@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.
-You can add @samp{TCPOnly = yes} to host configuration files to force all VPN traffic to go over a TCP connection.
-@end itemize
-
-@item Got bad/bogus/unauthorized REQUEST from foo (1.2.3.4 port 12345)
-
-@itemize
-@item Node foo does not have the right public/private keypair.
-Generate new keypairs and distribute them again.
-@item An attacker tries to gain access to your VPN.
-@item A network error caused corruption of metadata sent from foo.
-@end itemize
-
-@end table
-
-@c ==================================================================
-@node Sending bug reports
-@section Sending bug reports
-
-If you really can't find the cause of a problem, or if you suspect tinc is not working right,
-you can send us a bugreport, see @ref{Contact information}.
-Be sure to include the following information in your bugreport:
-
-@itemize
-@item A clear description of what you are trying to achieve and what the problem is.
-@item What platform (operating system, version, hardware architecture) and which version of tinc you use.
-@item If compiling tinc fails, a copy of @file{config.log} and the error messages you get.
-@item Otherwise, a copy of @file{tinc.conf}, @file{tinc-up} and all files in the @file{hosts/} directory.
-@item The output of the commands @samp{ifconfig -a} and @samp{route -n} (or @samp{netstat -rn} if that doesn't work).
-@item The output of any command that fails to work as it should (like ping or traceroute).
-@end itemize
-
-@c ==================================================================
-@node Controlling tinc
-@chapter Controlling tinc
-
-@cindex command line interface
-You can start, stop, control and inspect a running tincd through the tinc
-command. A quick example:
-
-@example
-tinc -n @var{netname} reload
-@end example
-
-@cindex shell
-If tinc is started without a command, it will act as a shell; it will display a
-prompt, and commands can be entered on the prompt. If tinc is compiled with
-libreadline, history and command completion are available on the prompt. One
-can also pipe a script containing commands through tinc. In that case, lines
-starting with a # symbol will be ignored.
-
-@menu
-* tinc runtime options::
-* tinc environment variables::
-* tinc commands::
-* tinc examples::
-* tinc top::
-@end menu
-
-
-@c ==================================================================
-@node tinc runtime options
-@section tinc runtime options
-
-@c from the manpage
-@table @option
-@item -c, --config=@var{path}
-Read configuration options from the directory @var{path}. The default is
-@file{@value{sysconfdir}/tinc/@var{netname}/}.
-
-@item -n, --net=@var{netname}
-Use configuration for net @var{netname}. @xref{Multiple networks}.
-
-@item --pidfile=@var{filename}
-Use the cookie from @var{filename} to authenticate with a running tinc daemon.
-If unspecified, the default is
-@file{@value{localstatedir}/run/tinc.@var{netname}.pid}.
-
-@item --help
-Display a short reminder of runtime options and commands, then terminate.
-
-@item --version
-Output version information and exit.
-
-@end table
-
-@c ==================================================================
-@node tinc environment variables
-@section tinc environment variables
-
-@table @env
-@cindex NETNAME
-@item NETNAME
-If no netname is specified on the command line with the @option{-n} option,
-the value of this environment variable is used.
-@end table
-
-@c ==================================================================
-@node tinc commands
-@section tinc commands
-
-@c from the manpage
-@table @code
-
-@cindex init
-@item init [@var{name}]
-Create initial configuration files and RSA and ECDSA keypairs with default length.
-If no @var{name} for this node is given, it will be asked for.
-
-@cindex get
-@item get @var{variable}
-Print the current value of configuration variable @var{variable}.
-If more than one variable with the same name exists,
-the value of each of them will be printed on a separate line.
-
-@cindex set
-@item set @var{variable} @var{value}
-Set configuration variable @var{variable} to the given @var{value}.
-All previously existing configuration variables with the same name are removed.
-To set a variable for a specific host, use the notation @var{host}.@var{variable}.
-
-@cindex add
-@item add @var{variable} @var{value}
-As above, but without removing any previously existing configuration variables.
-
-@cindex del
-@item del @var{variable} [@var{value}]
-Remove configuration variables with the same name and @var{value}.
-If no @var{value} is given, all configuration variables with the same name will be removed.
-
-@cindex edit
-@item edit @var{filename}
-Start an editor for the given configuration file.
-You do not need to specify the full path to the file.
-
-@cindex export
-@item export
-Export the host configuration file of the local node to standard output.
-
-@cindex export-all
-@item export-all
-Export all host configuration files to standard output.
-
-@cindex import
-@item import [--force]
-Import host configuration file(s) generated by the tinc export command from standard input.
-Already existing host configuration files are not overwritten unless the option --force is used.
-
-@cindex exchange
-@item exchange [--force]
-The same as export followed by import.
-
-@cindex exchange-all
-@item exchange-all [--force]
-The same as export-all followed by import.
-
-@cindex invite
-@item invite @var{name}
-Prepares an invitation for a new node with the given @var{name},
-and prints a short invitation URL that can be used with the join command.
-
-@cindex join
-@item join [@var{URL}]
-Join an existing VPN using an invitation URL created using the invite command.
-If no @var{URL} is given, it will be read from standard input.
-
-@cindex start
-@item start [tincd options]
-Start @samp{tincd}, optionally with the given extra options.
-
-@cindex stop
-@item stop
-Stop @samp{tincd}.
-
-@cindex restart
-@item restart [tincd options]
-Restart @samp{tincd}, optionally with the given extra options.
-
-@cindex reload
-@item reload
-Partially rereads configuration files. Connections to hosts whose host
-config files are removed are closed. New outgoing connections specified
-in @file{tinc.conf} will be made.
-
-@cindex pid
-@item pid
-Shows the PID of the currently running @samp{tincd}.
-
-@cindex generate-keys
-@item generate-keys [@var{bits}]
-Generate both RSA and ECDSA keypairs (see below) and exit.
-tinc will ask where you want to store the files, but will default to the
-configuration directory (you can use the -c or -n option).
-
-@cindex generate-ecdsa-keys
-@item generate-ecdsa-keys
-Generate public/private ECDSA keypair and exit.
-
-@cindex generate-rsa-keys
-@item generate-rsa-keys [@var{bits}]
-Generate public/private RSA keypair and exit. If @var{bits} is omitted, the
-default length will be 2048 bits. When saving keys to existing files, tinc
-will not delete the old keys; you have to remove them manually.
-
-@cindex dump
-@item dump [reachable] nodes
-Dump a list of all known nodes in the VPN.
-If the reachable keyword is used, only lists reachable nodes.
-
-@item dump edges
-Dump a list of all known connections in the VPN.
-
-@item dump subnets
-Dump a list of all known subnets in the VPN.
-
-@item dump connections
-Dump a list of all meta connections with ourself.
-
-@cindex graph
-@item dump graph | digraph
-Dump a graph of the VPN in dotty format.
-Nodes are colored according to their reachability:
-red nodes are unreachable, orange nodes are indirectly reachable, green nodes are directly reachable.
-Black nodes are either directly or indirectly reachable, but direct reachability has not been tried yet.
-
-@cindex info
-@item info @var{node} | @var{subnet} | @var{address}
-Show information about a particular @var{node}, @var{subnet} or @var{address}.
-If an @var{address} is given, any matching subnet will be shown.
-
-@cindex purge
-@item purge
-Purges all information remembered about unreachable nodes.
-
-@cindex debug
-@item debug @var{level}
-Sets debug level to @var{level}.
-
-@cindex log
-@item log [@var{level}]
-Capture log messages from a running tinc daemon.
-An optional debug level can be given that will be applied only for log messages sent to tinc.
-
-@cindex retry
-@item retry
-Forces tinc to try to connect to all uplinks immediately.
-Usually tinc attempts to do this itself,
-but increases the time it waits between the attempts each time it failed,
-and if tinc didn't succeed to connect to an uplink the first time after it started,
-it defaults to the maximum time of 15 minutes.
-
-@cindex disconnect
-@item disconnect @var{node}
-Closes the meta connection with the given @var{node}.
-
-@cindex top
-@item top
-If tinc is compiled with libcurses support, this will display live traffic statistics for all the known nodes,
-similar to the UNIX top command.
-See below for more information.
-
-@cindex pcap
-@item pcap
-Dump VPN traffic going through the local tinc node in pcap-savefile format to standard output,
-from where it can be redirected to a file or piped through a program that can parse it directly,
-such as tcpdump.
-
-@cindex network [@var{netname}]
-@item network
-If @var{netname} is given, switch to that network.
-Otherwise, display a list of all networks for which configuration files exist.
-
-@end table
-
-@c ==================================================================
-@node tinc examples
-@section tinc examples
-
-Examples of some commands:
-
-@example
-tinc -n vpn dump graph | circo -Txlib
-tinc -n vpn pcap | tcpdump -r -
-tinc -n vpn top
-@end example
-
-Examples of changing the configuration using tinc:
-
-@example
-tinc -n vpn init foo
-tinc -n vpn add Subnet 192.168.1.0/24
-tinc -n vpn add bar.Address bar.example.com
-tinc -n vpn add ConnectTo bar
-tinc -n vpn export | gpg --clearsign | mail -s "My config" vpnmaster@@example.com
-@end example
-
-@c ==================================================================
-@node tinc top
-@section tinc top
-
-@cindex top
-The top command connects to a running tinc daemon and repeatedly queries its per-node traffic counters.
-It displays a list of all the known nodes in the left-most column,
-and the amount of bytes and packets read from and sent to each node in the other columns.
-By default, the information is updated every second.
-The behaviour of the top command can be changed using the following keys:
-
-@table @key
-
-@item s
-Change the interval between updates.
-After pressing the @key{s} key, enter the desired interval in seconds, followed by enter.
-Fractional seconds are honored.
-Intervals lower than 0.1 seconds are not allowed.
-
-@item c
-Toggle between displaying current traffic rates (in packets and bytes per second)
-and cummulative traffic (total packets and bytes since the tinc daemon started).
-
-@item n
-Sort the list of nodes by name.
-
-@item i
-Sort the list of nodes by incoming amount of bytes.
-
-@item I
-Sort the list of nodes by incoming amount of packets.
-
-@item o
-Sort the list of nodes by outgoing amount of bytes.
-
-@item O
-Sort the list of nodes by outgoing amount of packets.
-
-@item t
-Sort the list of nodes by sum of incoming and outgoing amount of bytes.
-
-@item T
-Sort the list of nodes by sum of incoming and outgoing amount of packets.
-
-@item b
-Show amount of traffic in bytes.
-
-@item k
-Show amount of traffic in kilobytes.
-
-@item M
-Show amount of traffic in megabytes.
-
-@item G
-Show amount of traffic in gigabytes.
-
-@item q
-Quit.
-
-@end table
-
-
-@c ==================================================================
-@node Technical information
-@chapter Technical information
-
-
-@menu
-* The connection::
-* The meta-protocol::
-* Security::
-@end menu
-
-
-@c ==================================================================
-@node The connection
-@section The connection
-
-@cindex connection
-Tinc is a daemon that takes VPN data and transmit that to another host
-computer over the existing Internet infrastructure.
-
-@menu
-* The UDP tunnel::
-* The meta-connection::
-@end menu
-
-
-@c ==================================================================
-@node The UDP tunnel
-@subsection The UDP tunnel
-
-@cindex virtual network device
-@cindex frame type
-The data itself is read from a character device file, the so-called
-@emph{virtual network device}. This device is associated with a network
-interface. Any data sent to this interface can be read from the device,
-and any data written to the device gets sent from the interface.
-There are two possible types of virtual network devices:
-`tun' style, which are point-to-point devices which can only handle IPv4 and/or IPv6 packets,
-and `tap' style, which are Ethernet devices and handle complete Ethernet frames.
-
-So when tinc reads an Ethernet frame from the device, it determines its
-type. When tinc is in it's default routing mode, it can handle IPv4 and IPv6
-packets. Depending on the Subnet lines, it will send the packets off to their destination IP address.
-In the `switch' and `hub' mode, tinc will use broadcasts and MAC address discovery
-to deduce the destination of the packets.
-Since the latter modes only depend on the link layer information,
-any protocol that runs over Ethernet is supported (for instance IPX and Appletalk).
-However, only `tap' style devices provide this information.
-
-After the destination has been determined,
-the packet will be compressed (optionally),
-a sequence number will be added to the packet,
-the packet will then be encrypted
-and a message authentication code will be appended.
-
-@cindex encapsulating
-@cindex UDP
-When that is done, time has come to actually transport the
-packet to the destination computer. We do this by sending the packet
-over an UDP connection to the destination host. This is called
-@emph{encapsulating}, the VPN packet (though now encrypted) is
-encapsulated in another IP datagram.
-
-When the destination receives this packet, the same thing happens, only
-in reverse. So it checks the message authentication code, decrypts the contents of the UDP datagram,
-checks the sequence number
-and writes the decrypted information to its own virtual network device.
-
-If the virtual network device is a `tun' device (a point-to-point tunnel),
-there is no problem for the kernel to accept a packet.
-However, if it is a `tap' device (this is the only available type on FreeBSD),
-the destination MAC address must match that of the virtual network interface.
-If tinc is in it's default routing mode, ARP does not work, so the correct destination MAC
-can not be known by the sending host.
-Tinc solves this by letting the receiving end detect the MAC address of its own virtual network interface
-and overwriting the destination MAC address of the received packet.
-
-In switch or hub modes ARP does work so the sender already knows the correct destination MAC address.
-In those modes every interface should have a unique MAC address, so make sure they are not the same.
-Because switch and hub modes rely on MAC addresses to function correctly,
-these modes cannot be used on the following operating systems which don't have a `tap' style virtual network device:
-OpenBSD, NetBSD, Darwin and Solaris.
-
-
-@c ==================================================================
-@node The meta-connection
-@subsection The meta-connection
-
-Having only a UDP connection available is not enough. Though suitable
-for transmitting data, we want to be able to reliably send other
-information, such as routing and session key information to somebody.
-
-@cindex TCP
-TCP is a better alternative, because it already contains protection
-against information being lost, unlike UDP.
-
-So we establish two connections. One for the encrypted VPN data, and one
-for other information, the meta-data. Hence, we call the second
-connection the meta-connection. We can now be sure that the
-meta-information doesn't get lost on the way to another computer.
-
-@cindex data-protocol
-@cindex meta-protocol
-Like with any communication, we must have a protocol, so that everybody
-knows what everything stands for, and how she should react. Because we
-have two connections, we also have two protocols. The protocol used for
-the UDP data is the ``data-protocol,'' the other one is the
-``meta-protocol.''
-
-The reason we don't use TCP for both protocols is that UDP is much
-better for encapsulation, even while it is less reliable. The real
-problem is that when TCP would be used to encapsulate a TCP stream
-that's on the private network, for every packet sent there would be
-three ACKs sent instead of just one. Furthermore, if there would be
-a timeout, both TCP streams would sense the timeout, and both would
-start re-sending packets.
-
-
-@c ==================================================================
-@node The meta-protocol
-@section The meta-protocol
-
-The meta protocol is used to tie all tinc daemons together, and
-exchange information about which tinc daemon serves which virtual
-subnet.
-
-The meta protocol consists of requests that can be sent to the other
-side. Each request has a unique number and several parameters. All
-requests are represented in the standard ASCII character set. It is
-possible to use tools such as telnet or netcat to connect to a tinc
-daemon started with the --bypass-security option
-and to read and write requests by hand, provided that one
-understands the numeric codes sent.
-
-The authentication scheme is described in @ref{Security}. After a
-successful authentication, the server and the client will exchange all the
-information about other tinc daemons and subnets they know of, so that both
-sides (and all the other tinc daemons behind them) have their information
-synchronised.
-
-@cindex ADD_EDGE
-@cindex ADD_SUBNET
-@example
-message
-------------------------------------------------------------------
-ADD_EDGE node1 node2 21.32.43.54 655 222 0
- | | | | | +-> options
- | | | | +----> weight
- | | | +--------> UDP port of node2
- | | +----------------> real address of node2
- | +-------------------------> name of destination node
- +-------------------------------> name of source node
-
-ADD_SUBNET node 192.168.1.0/24
- | | +--> prefixlength
- | +--------> network address
- +------------------> owner of this subnet
-------------------------------------------------------------------
-@end example
-
-The ADD_EDGE messages are to inform other tinc daemons that a connection between
-two nodes exist. The address of the destination node is available so that
-VPN packets can be sent directly to that node.
-
-The ADD_SUBNET messages inform other tinc daemons that certain subnets belong
-to certain nodes. tinc will use it to determine to which node a VPN packet has
-to be sent.
-
-@cindex DEL_EDGE
-@cindex DEL_SUBNET
-@example
-message
-------------------------------------------------------------------
-DEL_EDGE node1 node2
- | +----> name of destination node
- +----------> name of source node
-
-DEL_SUBNET node 192.168.1.0/24
- | | +--> prefixlength
- | +--------> network address
- +------------------> owner of this subnet
-------------------------------------------------------------------
-@end example
-
-In case a connection between two daemons is closed or broken, DEL_EDGE messages
-are sent to inform the other daemons of that fact. Each daemon will calculate a
-new route to the the daemons, or mark them unreachable if there isn't any.
-
-@cindex REQ_KEY
-@cindex ANS_KEY
-@cindex KEY_CHANGED
-@example
-message
-------------------------------------------------------------------
-REQ_KEY origin destination
- | +--> name of the tinc daemon it wants the key from
- +----------> name of the daemon that wants the key
-
-ANS_KEY origin destination 4ae0b0a82d6e0078 91 64 4
- | | \______________/ | | +--> MAC length
- | | | | +-----> digest algorithm
- | | | +--------> cipher algorithm
- | | +--> 128 bits key
- | +--> name of the daemon that wants the key
- +----------> name of the daemon that uses this key
-
-KEY_CHANGED origin
- +--> daemon that has changed it's packet key
-------------------------------------------------------------------
-@end example
-
-The keys used to encrypt VPN packets are not sent out directly. This is
-because it would generate a lot of traffic on VPNs with many daemons, and
-chances are that not every tinc daemon will ever send a packet to every
-other daemon. Instead, if a daemon needs a key it sends a request for it
-via the meta connection of the nearest hop in the direction of the
-destination.
-
-@cindex PING
-@cindex PONG
-@example
-daemon message
-------------------------------------------------------------------
-origin PING
-dest. PONG
-------------------------------------------------------------------
-@end example
-
-There is also a mechanism to check if hosts are still alive. Since network
-failures or a crash can cause a daemon to be killed without properly
-shutting down the TCP connection, this is necessary to keep an up to date
-connection list. PINGs are sent at regular intervals, except when there
-is also some other traffic. A little bit of salt (random data) is added
-with each PING and PONG message, to make sure that long sequences of PING/PONG
-messages without any other traffic won't result in known plaintext.
-
-This basically covers what is sent over the meta connection by tinc.
-
-
-@c ==================================================================
-@node Security
-@section Security
-
-@cindex TINC
-@cindex Cabal
-Tinc got its name from ``TINC,'' short for @emph{There Is No Cabal}; the
-alleged Cabal was/is an organisation that was said to keep an eye on the
-entire Internet. As this is exactly what you @emph{don't} want, we named
-the tinc project after TINC.
-
-@cindex SVPN
-But in order to be ``immune'' to eavesdropping, you'll have to encrypt
-your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does
-exactly that: encrypt.
-However, encryption in itself does not prevent an attacker from modifying the encrypted data.
-Therefore, tinc also authenticates the data.
-Finally, tinc uses sequence numbers (which themselves are also authenticated) to prevent an attacker from replaying valid packets.
-
-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.
-The SPTPS protocol is designed to address some weaknesses in the legacy protocol.
-The new authentication protocol is used when two nodes connect to each other that both have the ExperimentalProtocol option set to yes,
-otherwise the legacy protocol will be used.
-
-@menu
-* Legacy authentication protocol::
-* Simple Peer-to-Peer Security::
-* Encryption of network packets::
-* Security issues::
-@end menu
-
-
-@c ==================================================================
-@node Legacy authentication protocol
-@subsection Legacy authentication protocol
-
-@cindex legacy authentication protocol
-
-@cindex ID
-@cindex META_KEY
-@cindex CHALLENGE
-@cindex CHAL_REPLY
-@cindex ACK
-@example
-daemon message
---------------------------------------------------------------------------
-client <attempts connection>
-
-server <accepts connection>
-
-client ID client 17.2
- | | +-> minor protocol version
- | +----> major protocol version
- +--------> name of tinc daemon
-
-server ID server 17.2
- | | +-> minor protocol version
- | +----> major protocol version
- +--------> name of tinc daemon
-
-client META_KEY 94 64 0 0 5f0823a93e35b69e...7086ec7866ce582b
- | | | | \_________________________________/
- | | | | +-> RSAKEYLEN bits totally random string S1,
- | | | | encrypted with server's public RSA key
- | | | +-> compression level
- | | +---> MAC length
- | +------> digest algorithm NID
- +---------> cipher algorithm NID
-
-server META_KEY 94 64 0 0 6ab9c1640388f8f0...45d1a07f8a672630
- | | | | \_________________________________/
- | | | | +-> RSAKEYLEN bits totally random string S2,
- | | | | encrypted with client's public RSA key
- | | | +-> compression level
- | | +---> MAC length
- | +------> digest algorithm NID
- +---------> cipher algorithm NID
---------------------------------------------------------------------------
-@end example
-
-The protocol allows each side to specify encryption algorithms and parameters,
-but in practice they are always fixed, since older versions of tinc did not
-allow them to be different from the default values. The cipher is always
-Blowfish in OFB mode, the digest is SHA1, but the MAC length is zero and no
-compression is used.
-
-From now on:
-@itemize
-@item the client will symmetrically encrypt outgoing traffic using S1
-@item the server will symmetrically encrypt outgoing traffic using S2
-@end itemize
-
-@example
---------------------------------------------------------------------------
-client CHALLENGE da02add1817c1920989ba6ae2a49cecbda0
- \_________________________________/
- +-> CHALLEN bits totally random string H1
-
-server CHALLENGE 57fb4b2ccd70d6bb35a64c142f47e61d57f
- \_________________________________/
- +-> CHALLEN bits totally random string H2
-
-client CHAL_REPLY 816a86
- +-> 160 bits SHA1 of H2
-
-server CHAL_REPLY 928ffe
- +-> 160 bits SHA1 of H1
-
-After the correct challenge replies are received, both ends have proved
-their identity. Further information is exchanged.
-
-client ACK 655 123 0
- | | +-> options
- | +----> estimated weight
- +--------> listening port of client
-
-server ACK 655 321 0
- | | +-> options
- | +----> estimated weight
- +--------> listening port of server
---------------------------------------------------------------------------
-@end example
-
-This legacy authentication protocol has several weaknesses, pointed out by security export Peter Gutmann.
-First, data is encrypted with RSA without padding.
-Padding schemes are designed to prevent attacks when the size of the plaintext is not equal to the size of the RSA key.
-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.
-There might be timing or other side-channel attacks against RSA encryption and decryption, tinc does not employ any protection against those.
-Furthermore, both sides send identical messages to each other, there is no distinction between server and client,
-which could make a MITM attack easier.
-However, no exploit is known in which a third party who is not already trusted by other nodes in the VPN could gain access.
-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.
-In other words, the legacy protocol does not provide perfect forward secrecy.
-
-@c ==================================================================
-@node Simple Peer-to-Peer Security
-@subsection Simple Peer-to-Peer Security
-@cindex SPTPS
-
-The SPTPS protocol is designed to address the weaknesses in the legacy protocol.
-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.
-Instead, SPTPS always uses a very strong cipher suite:
-peers authenticate each other using 521 bits ECC keys,
-Diffie-Hellman using ephemeral 521 bits ECC keys is used to provide perfect forward secrecy (PFS),
-AES-256-CTR is used for encryption, and HMAC-SHA-256 for message authentication.
-
-Similar to TLS, messages are split up in records.
-A complete logical record contains the following information:
-
-@itemize
-@item uint32_t seqno (network byte order)
-@item uint16_t length (network byte order)
-@item uint8_t type
-@item opaque data[length]
-@item opaque hmac[HMAC_SIZE] (HMAC over all preceding fields)
-@end itemize
-
-Depending on whether SPTPS records are sent via TCP or UDP, either the seqno or the length field is omitted on the wire
-(but they are still included in the calculation of the HMAC);
-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;
-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.
-
-The type field is used to distinguish between application records or handshake records.
-Types 0 to 127 are application records, type 128 is a handshake record, and types 129 to 255 are reserved.
-
-Before the initial handshake, no fields are encrypted, and the HMAC field is not present.
-After the authentication handshake, the length (if present), type and data fields are encrypted, and the HMAC field is present.
-For UDP packets, the seqno field is not encrypted, as it is used to determine the value of the counter used for encryption.
-
-The authentication consists of an exchange of Key EXchange, SIGnature and ACKnowledge messages, transmitted using type 128 records.
-
-Overview:
-
-@example
-Initiator Responder
----------------------
-KEX ->
- <- KEX
-SIG ->
- <- SIG
-
-...encrypt and HMAC using session keys from now on...
-
-App ->
- <- App
-...
- ...
-
-...key renegotiation starts here...
-
-KEX ->
- <- KEX
-SIG ->
- <- SIG
-ACK ->
- <- ACK
-
-...encrypt and HMAC using new session keys from now on...
-
-App ->
- <- App
-...
- ...
----------------------
-@end example
-
-Note that the responder does not need to wait before it receives the first KEX message,
-it can immediately send its own once it has accepted an incoming connection.
-
-Key EXchange message:
-
-@itemize
-@item uint8_t kex_version (always 0 in this version of SPTPS)
-@item opaque nonce[32] (random number)
-@item opaque ecdh_key[ECDH_SIZE]
-@end itemize
-
-SIGnature message:
-
-@itemize
-@item opaque ecdsa_signature[ECDSA_SIZE]
-@end itemize
-
-ACKnowledge message:
-
-@itemize
-@item empty (only sent after key renegotiation)
-@end itemize
-
-Remarks:
-
-@itemize
-@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.
-@item After receiving the other's KEX message, both KEX messages are concatenated (see below),
- and the result is signed using ECDSA.
- The result is sent to the other.
-@item After receiving the other's SIG message, the signature is verified.
- 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.
-@item The shared secret key is expanded using a PRF.
- Both nonces and the application specific label are also used as input for the PRF.
-@item An ACK message is sent only when doing key renegotiation, and is sent using the old encryption keys.
-@item The expanded key is used to key the encryption and HMAC algorithms.
-@end itemize
-
-The signature is calculated over this string:
-
-@itemize
-@item uint8_t initiator (0 = local peer, 1 = remote peer is initiator)
-@item opaque remote_kex_message[1 + 32 + ECDH_SIZE]
-@item opaque local_kex_message[1 + 32 + ECDH_SIZE]
-@item opaque label[label_length]
-@end itemize
-
-The PRF is calculated as follows:
-
-@itemize
-@item A HMAC using SHA512 is used, the shared secret is used as the key.
-@item For each block of 64 bytes, a HMAC is calculated. For block n: hmac[n] =
- HMAC_SHA512(hmac[n - 1] + seed)
-@item For the first block (n = 1), hmac[0] is given by HMAC_SHA512(zeroes + seed),
- where zeroes is a block of 64 zero bytes.
-@end itemize
-
-The seed is as follows:
-
-@itemize
-@item const char[13] "key expansion"
-@item opaque responder_nonce[32]
-@item opaque initiator_nonce[32]
-@item opaque label[label_length]
-@end itemize
-
-The expanded key is used as follows:
-
-@itemize
-@item opaque responder_cipher_key[CIPHER_KEYSIZE]
-@item opaque responder_digest_key[DIGEST_KEYSIZE]
-@item opaque initiator_cipher_key[CIPHER_KEYSIZE]
-@item opaque initiator_digest_key[DIGEST_KEYSIZE]
-@end itemize
-
-Where initiator_cipher_key is the key used by session initiator to encrypt
-messages sent to the responder.
-
-When using 521 bits EC keys, the AES-256-CTR cipher and HMAC-SHA-256 digest algorithm,
-the sizes are as follows:
-
-@example
-ECDH_SIZE: 67 (= ceil(521/8) + 1)
-ECDSA_SIZE: 141 (= 2 * ceil(521/8) + 9)
-CIPHER_KEYSIZE: 48 (= 256/8 + 128/8)
-DIGEST_KEYSIZE: 32 (= 256/8)
-@end example
-
-Note that the cipher key also includes the initial value for the counter.
-
-@c ==================================================================
-@node Encryption of network packets
-@subsection Encryption of network packets
-@cindex encryption
-
-A data packet can only be sent if the encryption key is known to both
-parties, and the connection is activated. If the encryption key is not
-known, a request is sent to the destination using the meta connection
-to retrieve it.
-
-@cindex UDP
-The UDP packets can be either encrypted with the legacy protocol or with SPTPS.
-In case of the legacy protocol, the UDP packet containing the network packet from the VPN has the following layout:
-
-@example
-... | IP header | UDP header | seqno | VPN packet | MAC | UDP trailer
- \___________________/\_____/
- | |
- V +---> digest algorithm
- Encrypted with symmetric cipher
-@end example
-
-
-
-
-So, the entire VPN packet is encrypted using a symmetric cipher, including a 32 bits
-sequence number that is added in front of the actual VPN packet, to act as a unique
-IV for each packet and to prevent replay attacks. A message authentication code
-is added to the UDP packet to prevent alteration of packets.
-Tinc by default encrypts network packets using Blowfish with 128 bit keys in CBC mode
-and uses 4 byte long message authentication codes to make sure
-eavesdroppers cannot get and cannot change any information at all from the
-packets they can intercept. The encryption algorithm and message authentication
-algorithm can be changed in the configuration. The length of the message
-authentication codes is also adjustable. The length of the key for the
-encryption algorithm is always the default length used by OpenSSL.
-
-The SPTPS protocol is described in @ref{Simple Peer-to-Peer Security}.
-For comparison, this is how SPTPS UDP packets look:
-
-@example
-... | IP header | UDP header | seqno | type | VPN packet | MAC | UDP trailer
- \__________________/\_____/
- | |
- V +---> digest algorithm
- Encrypted with symmetric cipher
-@end example
-
-The difference is that the seqno is not encrypted, since the encryption cipher is used in CTR mode,
-and therefore the seqno must be known before the packet can be decrypted.
-Furthermore, the MAC is never truncated.
-The SPTPS protocol always uses the AES-256-CTR cipher and HMAC-SHA-256 digest,
-this cannot be changed.
-
-
-@c ==================================================================
-@node Security issues
-@subsection Security issues
-
-In August 2000, we discovered the existence of a security hole in all versions
-of tinc up to and including 1.0pre2. This had to do with the way we exchanged
-keys. Since then, we have been working on a new authentication scheme to make
-tinc as secure as possible. The current version uses the OpenSSL library and
-uses strong authentication with RSA keys.
-
-On the 29th of December 2001, Jerome Etienne posted a security analysis of tinc
-1.0pre4. Due to a lack of sequence numbers and a message authentication code
-for each packet, an attacker could possibly disrupt certain network services or
-launch a denial of service attack by replaying intercepted packets. The current
-version adds sequence numbers and message authentication codes to prevent such
-attacks.
-
-On the 15th of September 2003, Peter Gutmann posted a security analysis of tinc
-1.0.1. He argues that the 32 bit sequence number used by tinc is not a good IV,
-that tinc's default length of 4 bytes for the MAC is too short, and he doesn't
-like tinc's use of RSA during authentication. We do not know of a security hole
-in the legacy protocol of tinc, but it is not as strong as TLS or IPsec.
-
-This version of tinc comes with an improved protocol, called Simple Peer-to-Peer Security,
-which aims to be as strong as TLS with one of the strongest cipher suites.
-
-Cryptography is a hard thing to get right. We cannot make any
-guarantees. Time, review and feedback are the only things that can
-prove the security of any cryptographic product. If you wish to review
-tinc or give us feedback, you are stronly encouraged to do so.
-
-
-@c ==================================================================
-@node Platform specific information
-@chapter Platform specific information
-
-@menu
-* Interface configuration::
-* Routes::
-@end menu
-
-@c ==================================================================
-@node Interface configuration
-@section Interface configuration
-
-When configuring an interface, one normally assigns it an address and a
-netmask. The address uniquely identifies the host on the network attached to
-the interface. The netmask, combined with the address, forms a subnet. It is
-used to add a route to the routing table instructing the kernel to send all
-packets which fall into that subnet to that interface. Because all packets for
-the entire VPN should go to the virtual network interface used by tinc, the
-netmask should be such that it encompasses the entire VPN.
-
-For IPv4 addresses:
-
-@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
-@item Linux
-@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
-@item Linux iproute2
-@tab @code{ip addr add} @var{address}@code{/}@var{prefixlength} @code{dev} @var{interface}
-@item FreeBSD
-@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
-@item OpenBSD
-@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
-@item NetBSD
-@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
-@item Solaris
-@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
-@item Darwin (MacOS/X)
-@tab @code{ifconfig} @var{interface} @var{address} @code{netmask} @var{netmask}
-@item Windows
-@tab @code{netsh interface ip set address} @var{interface} @code{static} @var{address} @var{netmask}
-@end multitable
-
-For IPv6 addresses:
-
-@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
-@item Linux
-@tab @code{ifconfig} @var{interface} @code{add} @var{address}@code{/}@var{prefixlength}
-@item FreeBSD
-@tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
-@item OpenBSD
-@tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
-@item NetBSD
-@tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
-@item Solaris
-@tab @code{ifconfig} @var{interface} @code{inet6 plumb up}
-@item
-@tab @code{ifconfig} @var{interface} @code{inet6 addif} @var{address} @var{address}
-@item Darwin (MacOS/X)
-@tab @code{ifconfig} @var{interface} @code{inet6} @var{address} @code{prefixlen} @var{prefixlength}
-@item Windows
-@tab @code{netsh interface ipv6 add address} @var{interface} @code{static} @var{address}/@var{prefixlength}
-@end multitable
-
-On some platforms, when running tinc in switch mode, the VPN interface must be set to tap mode with an ifconfig command:
-
-@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
-@item OpenBSD
-@tab @code{ifconfig} @var{interface} @code{link0}
-@end multitable
-
-On Linux, it is possible to create a persistent tun/tap interface which will
-continue to exist even if tinc quit, although this is normally not required.
-It can be useful to set up a tun/tap interface owned by a non-root user, so
-tinc can be started without needing any root privileges at all.
-
-@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
-@item Linux
-@tab @code{ip tuntap add dev} @var{interface} @code{mode} @var{tun|tap} @code{user} @var{username}
-@end multitable
-
-@c ==================================================================
-@node Routes
-@section Routes
-
-In some cases it might be necessary to add more routes to the virtual network
-interface. There are two ways to indicate which interface a packet should go
-to, one is to use the name of the interface itself, another way is to specify
-the (local) address that is assigned to that interface (@var{local_address}). The
-former way is unambiguous and therefore preferable, but not all platforms
-support this.
-
-Adding routes to IPv4 subnets:
-
-@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
-@item Linux
-@tab @code{route add -net} @var{network_address} @code{netmask} @var{netmask} @var{interface}
-@item Linux iproute2
-@tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
-@item FreeBSD
-@tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
-@item OpenBSD
-@tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
-@item NetBSD
-@tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
-@item Solaris
-@tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
-@item Darwin (MacOS/X)
-@tab @code{route add} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
-@item Windows
-@tab @code{netsh routing ip add persistentroute} @var{network_address} @var{netmask} @var{interface} @var{local_address}
-@end multitable
-
-Adding routes to IPv6 subnets:
-
-@multitable {Darwin (MacOS/X)} {ifconfig route add -bla network address netmask netmask prefixlength interface}
-@item Linux
-@tab @code{route add -A inet6} @var{network_address}@code{/}@var{prefixlength} @var{interface}
-@item Linux iproute2
-@tab @code{ip route add} @var{network_address}@code{/}@var{prefixlength} @code{dev} @var{interface}
-@item FreeBSD
-@tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address}
-@item OpenBSD
-@tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
-@item NetBSD
-@tab @code{route add -inet6} @var{network_address} @var{local_address} @code{-prefixlen} @var{prefixlength}
-@item Solaris
-@tab @code{route add -inet6} @var{network_address}@code{/}@var{prefixlength} @var{local_address} @code{-interface}
-@item Darwin (MacOS/X)
-@tab ?
-@item Windows
-@tab @code{netsh interface ipv6 add route} @var{network address}/@var{prefixlength} @var{interface}
-@end multitable
-
-
-@c ==================================================================
-@node About us
-@chapter About us
-
-
-@menu
-* Contact information::
-* Authors::
-@end menu
-
-
-@c ==================================================================
-@node Contact information
-@section Contact information
-
-@cindex website
-Tinc's website is at @url{http://www.tinc-vpn.org/},
-this server is located in the Netherlands.
-
-@cindex IRC
-We have an IRC channel on the FreeNode and OFTC IRC networks. Connect to
-@uref{http://www.freenode.net/, irc.freenode.net}
-or
-@uref{http://www.oftc.net/, irc.oftc.net}
-and join channel #tinc.
-
-
-@c ==================================================================
-@node Authors
-@section Authors
-
-@table @asis
-@item Ivo Timmermans (zarq)
-@item Guus Sliepen (guus) (@email{guus@@tinc-vpn.org})
-@end table
-
-We have received a lot of valuable input from users. With their help,
-tinc has become the flexible and robust tool that it is today. We have
-composed a list of contributions, in the file called @file{THANKS} in
-the source distribution.
-
-
-@c ==================================================================
-@node Concept Index
-@unnumbered Concept Index
+@c ==================================================================
+@node Concept Index
+@unnumbered Concept Index
@c ==================================================================
@printindex cp
-
@c ==================================================================
@contents
@bye
projects / meshlink / commitdiff