\input texinfo @c -*-texinfo-*-
+@c $Id: tinc.texi,v 1.8.4.33 2002/10/07 07:32:31 guus Exp $
@c %**start of header
@setfilename tinc.info
@settitle tinc Manual
@c %**end of header
@ifinfo
+@dircategory Networking tools
@direntry
* tinc: (tinc). The tinc Manual.
@end direntry
This is the info manual for tinc, a Virtual Private Network daemon.
-Copyright 1998,199,2000 Ivo Timmermans <itimmermans@@bigfoot.com>
+Copyright @copyright{} 1998-2002 Ivo Timmermans
+<ivo@@o2w.nl>, Guus Sliepen <guus@@sliepen.eu.org> and
+Wessel Dankers <wsl@@nl.linux.org>.
- Permission is granted to make and distribute verbatim
- copies of this manual provided the copyright notice and
- this permission notice are preserved on all copies.
+$Id: tinc.texi,v 1.8.4.33 2002/10/07 07:32:31 guus Exp $
- Permission is granted to copy and distribute modified
- versions of this 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.
+Permission is granted to make and distribute verbatim copies of this
+manual provided the copyright notice and this permission notice are
+preserved on all copies.
+
+Permission is granted to copy and distribute modified versions of this
+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
@titlepage
@title tinc Manual
@subtitle Setting up a Virtual Private Network with tinc
-@author Ivo Timmermans <itimmermans@@bigfoot.com> and Guus Sliepen <guus@sliepen.warande.net>
+@author Ivo Timmermans and Guus Sliepen
@page
@vskip 0pt plus 1filll
-Copyright @copyright{} 1998,1999,2000 Ivo Timmermans <itimmermans@@bigfoot.com>
+@cindex copyright
+Copyright @copyright{} 1998-2002 Ivo Timmermans
+<ivo@@o2w.nl>, Guus Sliepen <guus@@sliepen.eu.org> and
+Wessel Dankers <wsl@@nl.linux.org>.
+
+$Id: tinc.texi,v 1.8.4.33 2002/10/07 07:32:31 guus Exp $
- Permission is granted to make and distribute verbatim
- copies of this manual provided the copyright notice and
- this permission notice are preserved on all copies.
+Permission is granted to make and distribute verbatim copies of this
+manual provided the copyright notice and this permission notice are
+preserved on all copies.
- Permission is granted to copy and distribute modified
- versions of this 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.
+Permission is granted to copy and distribute modified versions of this
+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
@menu
* Introduction:: Introduction
-* Configuring a Linux system:: Before compiling tinc
-* Installing tinc::
-* Configuring tinc::
-* Running tinc::
-* Technical information::
-* About us::
+* Preparations::
+* Installation::
+* Configuration::
+* Running tinc::
+* Technical information::
+* About us::
* Concept Index:: All used terms explained
@end menu
+
+@contents
+
@c ==================================================================
-@node Introduction, Configuring a Linux system, Top, Top
+@node Introduction, Preparations, Top, Top
@chapter Introduction
-@c straight from the www page
-
+@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.
-
-This tunneling allows VPN sites to share information with each other
+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
+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
* VPNs:: Virtual Private Networks in general
* tinc:: about tinc
+* Supported platforms::
@end menu
@c ==================================================================
@node VPNs, tinc, Introduction, Introduction
@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
+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,
+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
+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.
+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 do not interfere with
-each other. Mostly, virtual networks appear like a singe LAN, even though
-they can span the entire world. But virtual networks can't be secured
+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 singe 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.
+through the Internet, where other people can look at it.
-When one introduces encryption, we can form a true VPN. Other people may
+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.
-
-@cindex virtual
-tinc uses normal IP datagrams to encapsulate data that goes over the VPN
-network link. In this case it's also clear that the network is
-@emph{virtual}, because no direct network link has to exist between to
-participants.
-
-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.
+through the VPN. This is what tinc was made for.
@c ==================================================================
-@node tinc, , VPNs, Introduction
+@node tinc, Supported platforms, VPNs, Introduction
@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 @emph{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 @samp{vpnd}.
+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 @samp{vpnd}.
Since then, a lot has changed---to say the least.
runtime-configurable---in short, it has become a full-fledged
professional package.
-A lot can---and will be---changed. I have a few things that I'd 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
+@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
+Meanwhile, we're always open-minded towards new ideas. And we're
available too.
@c ==================================================================
-@node Configuring a Linux system, Installing tinc, Introduction, Top
-@chapter Configuring a Linux system
+@node Supported platforms, , tinc, Introduction
+@section Supported platforms
+
+@cindex platforms
+tinc has been verified to work under Linux, FreeBSD, OpenBSD and Solaris, 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://tinc.nl.linux.org/platforms.html}.
+
+
+@c ==================================================================
+@subsection Linux
+
+@cindex Linux
+tinc was first written for Linux running on an intel x86 processor, so
+this is the best supported platform. The protocol however, and actually
+anything about tinc, has been rewritten to support random byte ordering
+and arbitrary word length. So in theory it should run on other
+processors that Linux runs on. It has already been verified to run on
+alpha and sparc processors as well.
+
+tinc uses the ethertap device or the universal tun/tap driver. The former is provided in the standard kernel
+from version 2.1.60 up to 2.3.x, but has been replaced in favour of the tun/tap driver in kernel versions 2.4.0 and later.
+
+
+@c ==================================================================
+@subsection FreeBSD
+
+@cindex FreeBSD
+tinc on FreeBSD relies on the universal tun/tap driver for its data
+acquisition from the kernel. Therefore, tinc will work on the same platforms
+as this driver. These are: FreeBSD 3.x, 4.x, 5.x.
+
+
+@c ==================================================================
+@subsection OpenBSD
+
+@cindex OpenBSD
+tinc on OpenBSD relies on the tun driver for its data
+acquisition from the kernel. It has been verified to work under at least OpenBSD 2.9.
+
+Tunneling IPv6 packets may not work on OpenBSD.
+
+
+@c ==================================================================
+@subsection Solaris
-This chapter contains information on how a Linux system is configured
-for the use of tinc.
+@c ==================================================================
+@subsection NetBSD
+
+@cindex NetBSD
+tinc on NetBSD relies on the tun driver for its data
+acquisition from the kernel. It has been verified to work under at least NetBSD 1.5.2.
+
+Tunneling IPv6 does not work on OpenBSD.
+
+
+@c ==================================================================
+@subsection Solaris
+
+@cindex Solaris
+tinc on Solaris relies on the universal tun/tap driver for its data
+acquisition from the kernel. Therefore, tinc will work on the same platforms
+as this driver. These are: Solaris 8 (SunOS 5.8).
+
+IPv6 packets cannot be tunneled on Solaris.
+
+@c ==================================================================
+@subsection Darwin (MacOS/X)
+
+@cindex Darwin
+@cindex MacOS/X
+tinc on Darwin relies on the tunnel driver for its data
+acquisition from the kernel. This driver is not part of Darwin but can be
+downloaded from @uref{http://chrisp.de/en/projects/tunnel.html}.
+
+IPv6 packets cannot be tunneled on Darwin.
+
+
+@c
+@c
+@c
+@c
+@c
+@c
+@c Preparing your system
+@c
+@c
+@c
+@c
+@c
+
+@c ==================================================================
+@node Preparations, Installation, Introduction, Top
+@chapter Preparations
+
+This chapter contains information on how to prepare your system to
+support tinc.
@menu
-* Configuring the kernel::
-* Files Needed::
-* Setting up the devices::
+* Configuring the kernel::
+* Libraries::
@end menu
@c ==================================================================
-@node Configuring the kernel, Files Needed, Configuring a Linux system, Configuring a Linux system
+@node Configuring the kernel, Libraries, Preparations, Preparations
@section Configuring the kernel
-Since this particular implementation only runs on 2.1 or higher Linux
-kernels, you should grab one (2.2 is current at this time). A 2.0 port
-is not really possible, unless someone tells me someone ported the
-ethertap and netlink devices back to 2.0.
+@cindex RedHat
+@cindex Debian
+@cindex netlink_dev
+@cindex tun
+@cindex ethertap
+If you are running Linux, chances are good that your kernel already supports
+all the devices that tinc needs for proper operation. For example, the
+standard kernel from Redhat Linux already has support for ethertap and netlink
+compiled in. Debian users can use the modconf utility to select the modules.
+If your Linux distribution supports this method of selecting devices, look out
+for something called `ethertap', and `netlink_dev' if it is using a kernel
+version prior to 2.4.0. In that case you will need both these devices. If you
+are using kernel 2.4.0 or later, you need to select `tun'.
+
+@cindex Kernel-HOWTO
+If you can install these devices in a similar manner, you may skip this section.
+Otherwise, you will have to recompile the kernel in order to turn on the required features.
+If you are unfamiliar with the process of configuring and compiling a new kernel,
+you should read the @uref{http://howto.linuxberg.com/LDP/HOWTO/Kernel-HOWTO.html, Kernel HOWTO} first.
-If you are unfamiliar with the process of configuring and compiling a
-new kernel, you should read the
-@uref{http://howto.linuxberg.com/LDP/HOWTO/Kernel-HOWTO.html, Kernel
-HOWTO} first. Do that now!
+@menu
+* Configuration of Linux kernels 2.1.60 up to 2.4.0::
+* Configuration of Linux kernels 2.4.0 and higher::
+* Configuration of FreeBSD kernels::
+* Configuration of OpenBSD kernels::
+* Configuration of NetBSD kernels::
+* Configuration of Solaris kernels::
+* Configuration of Darwin (MacOS/X) kernels::
+@end menu
-Here are the options you have to turn on/off when configuring a new
-kernel.
+
+@c ==================================================================
+@node Configuration of Linux kernels 2.1.60 up to 2.4.0, Configuration of Linux kernels 2.4.0 and higher, Configuring the kernel, Configuring the kernel
+@subsection Configuration of Linux kernels 2.1.60 up to 2.4.0
+
+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
Networking options
[*] Kernel/User netlink socket
-<*> Netlink device emulation
+<M> Netlink device emulation
Network device support
-<*> Ethertap network tap
+<M> Ethertap network tap
@end example
-Any other options not mentioned here are not relevant to tinc. If you
-decide to build any of these as dynamic kernel modules, it's a good idea
-to add these lines to @file{/etc/modules.conf}.
+If you want to run more than one instance of tinc or other programs that use
+the ethertap, you have to compile the ethertap driver as a module, otherwise
+you can also choose to compile it directly into the kernel.
+
+If you decide to build any of these as dynamic kernel modules, it's a good idea
+to add these lines to @file{/etc/modules.conf}:
@example
-alias tap0 ethertap
alias char-major-36 netlink_dev
+alias tap0 ethertap
+options tap0 -o tap0 unit=0
+alias tap1 ethertap
+options tap1 -o tap1 unit=1
+...
+alias tap@emph{N} ethertap
+options tap@emph{N} -o tap@emph{N} unit=@emph{N}
@end example
-Finally, after having set up other options, build the kernel and boot
-it. Unfortunately it's not possible to insert these modules in a running
-kernel.
+Add as much alias/options lines as necessary.
@c ==================================================================
-@node Files Needed, Setting up the devices, Configuring the kernel, Configuring a Linux system
-@section Files Needed
+@node Configuration of Linux kernels 2.4.0 and higher, Configuration of FreeBSD kernels, Configuration of Linux kernels 2.1.60 up to 2.4.0, Configuring the kernel
+@subsection Configuration of Linux kernels 2.4.0 and higher
-@subsubheading Device files
+Here are the options you have to turn on when configuring a new kernel:
-First, you'll need the special device file(s) that form the interface
-between the kernel and the daemon. If you are running the new 2.4 kernel and
-you are using the devfs filesystem, then the tap device will be automatically
-generated as @file{/dev/netlink/tap0}. Otherwise, you have to make it yourself:
+@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 have an early 2.4 kernel, you can choose both the tun/tap driver and the
+`Ethertap network tap' device. This latter is marked obsolete, and chances are
+that it won't even function correctly anymore. Make sure you select the
+universal tun/tap driver.
+
+If you decide to build the tun/tap driver as a kernel module, add these lines
+to @file{/etc/modules.conf}:
@example
-mknod -m 600 /dev/tap0 c 36 16
-chown 0.0 /dev/tap0
+alias char-major-10-200 tun
@end example
-The permissions now will be such that only the super user may read/write
-to this file. You'd want this, because otherwise eavesdropping would
-become a bit too easy. This does, however, imply that you'd have to run
-tincd as root.
-If you want to, you may also create more device files, which would be
-numbered 0...15, with minor device numbers 16...31. They all should be
-owned by root and have permission 600. Under devfs, these files will
-be automatically generated.
+@c ==================================================================
+@node Configuration of FreeBSD kernels, Configuration of OpenBSD kernels, Configuration of Linux kernels 2.4.0 and higher, Configuring the kernel
+@subsection Configuration of FreeBSD kernels
+This section will contain information on how to configure your FreeBSD
+kernel to support the universal tun/tap device. For 4.1 and higher
+versions, this is included in the default kernel configuration, for earlier
+systems (4.0 and earlier), you need to install the universal tun/tap driver
+yourself.
-@subsubheading @file{/etc/networks}
+Unfortunately somebody still has to write the text.
-You may add a line to @file{/etc/networks} so that your VPN will get a
-symbolic name. For example:
+
+@c ==================================================================
+@node Configuration of OpenBSD kernels, Configuration of NetBSD kernels, Configuration of FreeBSD kernels, Configuring the kernel
+@subsection Configuration of OpenBSD kernels
+
+This section will contain information on how to configure your OpenBSD
+kernel to support the tun device. For 2.9 and 3.0 systems,
+this is included in the default kernel configuration.
+
+Unfortunately somebody still has to write the text.
+
+
+@c ==================================================================
+@node Configuration of NetBSD kernels, Configuration of Solaris kernels, Configuration of OpenBSD kernels, Configuring the kernel
+@subsection Configuration of NetBSD kernels
+
+This section will contain information on how to configure your NetBSD
+kernel to support the tun device. For 1.5.2 systems,
+this is included in the default kernel configuration.
+
+Unfortunately somebody still has to write the text.
+
+
+@c ==================================================================
+@node Configuration of Solaris kernels, Configuration of Darwin (MacOS/X) kernels, Configuration of NetBSD kernels, Configuring the kernel
+@subsection Configuration of Solaris kernels
+
+This section will contain information on how to configure your Solaris
+kernel to support the universal tun/tap device. For Solaris 8 (SunOS 5.8),
+this is included in the default kernel configuration.
+
+Unfortunately somebody still has to write the text.
+
+
+@c ==================================================================
+@node Configuration of Darwin (MacOS/X) kernels, , Configuration of Solaris kernels, Configuring the kernel
+@subsection Configuration of Darwin (MacOS/X) kernels
+
+Darwin does not come with a tunnel driver. You must download it at
+@uref{http://chrisp.de/en/projects/tunnel.html}. If compiling the source fails,
+try the binary module. The tunnel driver must be loaded before starting tinc
+with the following command:
@example
-myvpn 10.0.0.0
+kmodload tunnel
@end example
-This has nothing to do with the MyVPNIP configuration variable that will be
-discussed later, it is only to make the output of the route command more
-legible.
+Once loaded, the tunnel driver will automatically create @file{/dev/tun0}..@file{/dev/tun3}
+and the corresponding network interfaces.
-@subsubheading @file{/etc/services}
-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.
+@c ==================================================================
+@node Libraries, , Configuring the kernel, Preparations
+@section Libraries
+
+@cindex requirements
+@cindex libraries
+Before you can configure or build tinc, you need to have the OpenSSL
+and zlib 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::
+@end menu
+
+
+@c ==================================================================
+@node OpenSSL, zlib, Libraries, Libraries
+@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 without having OpenSSL
+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
-tinc 655/tcp TINC
-tinc 655/udp TINC
-# Ivo Timmermans <itimmermans@@bigfoot.com>
+--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
+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}, therefore we
+include an addition to the GPL (see also the file COPYING.README):
+
+@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
+
+
@c ==================================================================
-@node Setting up the devices, , Files Needed, Configuring a Linux system
-@section Setting up the devices
+@node zlib, , OpenSSL, Libraries
+@subsection zlib
-Before you can start transmitting data over the tinc tunnel, you must
-set up the ethertap network devices.
+@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 configuring
+tinc for build. Support for running tinc without having zlib
+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 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
+@c
+@c
+@c Installing tinc
+@c
+@c
+@c
+@c
+
+@c ==================================================================
+@node Installation, Configuration, Preparations, Top
+@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://tinc.nl.linux.org/download.html, 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, System files, Installation, Installation
+@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::
+@end menu
+
+
+@c ==================================================================
+@node Darwin (MacOS/X) build environment, , , Building and installing tinc
+@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://fink.sourceforge.net/}.
+
+After installation use fink to download and install the following packages:
+autoconf25, automake, dlcompat, m4, openssl and zlib.
+
+
+@c ==================================================================
+@node System files, , Building and installing tinc, Installation
+@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
-First, decide which IP addresses you want to have associated with these
-devices, and what network mask they must have. You also need these
-numbers when you are going to configure tinc itself. @xref{Configuring
-tinc}.
-It doesn't matter much which part you do first, setting up the network
-devices or configure tinc. But they both have to be done before you try
-to start a tincd.
+@c ==================================================================
+@node Device files, Other files, System files, System files
+@subsection Device files
+
+@cindex device files
+First, you'll need the special device file(s) that form the interface
+between the kernel and the daemon.
-The actual setup of the ethertap device is quite simple, just repeat
-after me:
+The permissions for these files have to be such that only the super user
+may read/write to this file. You'd want this, because otherwise
+eavesdropping would become a bit too easy. This does, however, imply
+that you'd have to run tincd as root.
+
+If you use Linux and have a kernel version prior to 2.4.0, you have to make the
+ethertap devices:
@example
-ifconfig tap@emph{n} hw ether fe:fd:@emph{xx}:@emph{xx}:@emph{xx}:@emph{xx}
+mknod -m 600 /dev/tap0 c 36 16
+mknod -m 600 /dev/tap1 c 36 17
+...
+mknod -m 600 /dev/tap@emph{N} c 36 @emph{N+16}
@end example
-The @emph{n} here is the number of the ethertap device you want to
-use. It should be the same @emph{n} as the one you use for
-@file{/dev/tap@emph{n}}. The @emph{xx}s are four hexadecimal numbers
-(0--ff). With previous versions of tincd, it didn't matter what they
-were. But newer kernels require properly set up ethernet addresses.
-In fact, the old behavior was wrong. It is required that the @emph{xx}s
-match the numbers of the IP address you will give to the tap device
-and to the MyOwnVPNIP configuration (which will be discussed later):
+There is a maximum of 16 ethertap devices.
+
+If you use the universal tun/tap driver, you have to create the
+following device file (unless it already exist):
@example
-ifconfig tap@emph{n} @emph{xx}.@emph{xx}.@emph{xx}.@emph{xx} netmask @emph{mask}
+mknod -m 600 /dev/tun c 10 200
@end example
-This will activate the device with an IP address @emph{IP} with network
-mask @emph{mask}. The netmask is the mask of the @emph{entire} VPN network,
-not just your own subnet. It is the same netmask you will have to specify
-with the VpnMask configuration variable.
+If you use Linux, and you run the new 2.4 kernel using the devfs filesystem,
+then the tun/tap device will probably be automatically generated as
+@file{/dev/net/tun}.
+
+Unlike the ethertap device, you do not need multiple device files if
+you are planning to run multiple tinc daemons.
@c ==================================================================
-@node Installing tinc, Configuring tinc, Configuring a Linux system, Top
-@chapter Installing tinc
+@node Other files, , Device files, System files
+@subsection Other files
-First download it. This is the
-@uref{http://tinc.nl.linux.org/download.html, download
-page}, which has the checksums of these files listed; you may wish to
-check these with md5sum before continuing.
+@subsubheading @file{/etc/networks}
-tinc comes in a handy autoconf/automake package, which you can just
-treat the same as any other package. Which is just untar it, type
-`configure' and then `make'.
+You may add a line to @file{/etc/networks} so that your VPN will get a
+symbolic name. For example:
-More detailed instructions are in the file @file{INSTALL}, which is
-included in the source distribution.
+@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@@o2w.nl>
+@end example
+
+
+@c
+@c
+@c
+@c
+@c Configuring tinc
+@c
+@c
+@c
+@c
@c ==================================================================
-@node Configuring tinc, Running tinc, Installing tinc, Top
-@chapter Configuring tinc
+@node Configuration, Running tinc, Installation, Top
+@chapter Configuration
@menu
-* Multiple networks::
-* How connections work::
-* Configuration file::
-* Example::
+* Configuration introduction::
+* Multiple networks::
+* How connections work::
+* Configuration files::
+* Generating keypairs::
+* Network interfaces::
+* Example configuration::
@end menu
+@c ==================================================================
+@node Configuration introduction, Multiple networks, Configuration, Configuration
+@section Configuration introduction
+
+@cindex Network Administrators Guide
+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?
+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.
+A good resource on networking is the
+@uref{http://www.linuxdoc.org/LDP/nag2/, Linux Network Administrators Guide}.
+
+If you have everything clearly pictured in your mind,
+proceed in the following order:
+First, generate the configuration files (@file{tinc.conf}, your host configuration file, @file{tinc-up} and perhaps @file{tinc-down}).
+Then generate the keypairs.
+Finally, distribute the host configuration files.
+These steps are described in the subsections below.
+
@c ==================================================================
-@node Multiple networks, How connections work, Configuring tinc, Configuring tinc
+@node Multiple networks, How connections work, Configuration introduction, Configuration
@section Multiple networks
-@c from the manpage
-
-It is perfectly OK for you to run more than one tinc daemon.
-However, in its default form, you will soon notice that you can't use
-two different configuration files without the -c option.
+@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 ``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 sites of your VPN,
+but it is recommended that you choose one anyway.
-We have thought of another way of dealing with this: network names. This
-means that you call tincd with the -n argument, which will assign a name
-to this daemon.
+We will asume you use a netname throughout this document.
+This means that you call tincd with the -n argument,
+which will assign a netname to this daemon.
The effect of this is that the daemon will set its configuration
-``root'' to /etc/tinc/nn/, where nn is your argument to the -n
-option. You'll notice that it appears in syslog as ``tinc.nn''.
+``root'' to /etc/tinc/netname/, where netname is your argument to the -n
+option. You'll notice that it appears in syslog as ``tinc.netname''.
However, it is not strictly necessary that you call tinc with the -n
-option. In this case, the network name would just be empty, and it will
-be used as such. tinc now looks for files in /etc/tinc/, instead of
-/etc/tinc/nn/; the configuration file should be /etc/tinc/tinc.conf,
-and the passphrases are now expected to be in /etc/tinc/passphrases/.
+option. In this case, the network name would just be empty, and it will
+be used as such. tinc now looks for files in /etc/tinc/, instead of
+/etc/tinc/netname/; the configuration file should be /etc/tinc/tinc.conf,
+and the host configuration files are now expected to be in /etc/tinc/hosts/.
But it is highly recommended that you use this feature of tinc, because
-it will be so much clearer whom your daemon talks to. Hence, we will
+it will be so much clearer whom your daemon talks to. Hence, we will
assume that you use it.
@c ==================================================================
-@node How connections work, Configuration file, Multiple networks, Configuring tinc
+@node How connections work, Configuration files, Multiple networks, Configuration
@section How connections work
-Before going on, first a bit on how tinc sees connections.
-
-When tinc starts up, it reads in the configuration file and parses the
-command-line options. If it sees a `ConnectTo' value in the file, it
-will try to connect to it, on the given port. If this fails, tinc exits.
+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.
@c ==================================================================
-@node Configuration file, Example, How connections work, Configuring tinc
-@section Configuration file
+@node Configuration files, Generating keypairs, How connections work, Configuration
+@section Configuration files
The actual configuration of the daemon is done in the file
-@file{/etc/tinc/nn/tinc.conf}.
+@file{/etc/tinc/netname/tinc.conf} and at least one other file in the directory
+@file{/etc/tinc/netname/hosts/}.
-This file consists of comments (lines started with a #) or assignments
+These file consists of comments (lines started with a #) or assignments
in the form of
@example
@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
+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.
+In this section all valid variables are listed in alphabetical order.
+The default value is given between parentheses,
+other comments are between square brackets and
+required directives are given in @strong{bold}.
+
@menu
-* Variables::
+* Main configuration variables::
+* Host configuration variables::
+* How to configure::
@end menu
-@c ==================================================================
-@node Variables, , Configuration file, Configuration file
-@subsection Variables
-Here are all valid variables, listed in alphabetical order. The default
-value, required or optional is given between parentheses.
+@c ==================================================================
+@node Main configuration variables, Host configuration variables, Configuration files, Configuration files
+@subsection Main configuration variables
-@c straight from the manpage
@table @asis
-@item ConnectPort = <port> (655)
-Connect to the upstream host (given with the ConnectTo directive) on
-port port. port may be given in decimal (default), octal (when preceded
-by a single zero) or hexadecimal (prefixed with 0x). port is the port
-number for both the UDP and the TCP (meta) connections.
-
-@item ConnectTo = <IP address|hostname> (optional)
-Specifies which host to connect to on startup. Multiple ConnectTo variables
-may be specified, if connecting to the first one fails then tinc will try
-the next one, and so on. It is possible to specify hostnames for dynamic IP
-addresses (like those given on dyndns.org), tinc will not cache the resolved
-IP address.
-
-If you don't specify a host with ConnectTo, regardless of whether a
-value for ConnectPort is given, tinc won't connect at all, and will
-instead just listen for incoming connections.
-
+@cindex AddressFamily
+@item AddressFamily = <ipv4|ipv6|any> (ipv4) [experimental]
+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 BindToAddress
+@item BindToAddress = <address> [experimental]
+If your computer has more than one IPv4 or IPv6 address, tinc
+will by default listen on all of them for incoming connections.
+It is possible to bind only to a single address with this variable.
+
+This option may not work on all platforms.
+
+@cindex BindToInterface
+@item BindToInterface = <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.
+
+@cindex ConnectTo
+@item @strong{ConnectTo = <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 Device
+@item @strong{Device = <device>} (/dev/tap0 or /dev/net/tun)
+The virtual network device to use. Note that you can only use one device per
+daemon. See also @ref{Device files}.
+
+@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 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.
+This does not affect resolving hostnames to IP addresses from the
+configuration file.
-@item IndirectData = <yes|no> (no)
-This option specifies whether other tinc daemons besides the one you
-specified with ConnectTo can make a direct connection to you. This is
-especially useful if you are behind a firewall and it is impossible
-to make a connection from the outside to your tinc daemon. Otherwise,
-it is best to leave this option out or set it to no.
-
-@item Interface = <device> (optional)
-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.
-
-@item InterfaceIP = <local address> (optional)
-If your computer has more than one IP address on a single interface (for example
-if you are running virtual hosts), tinc will by default listen on all of them for
-incoming connections. It is possible to bind tinc to a single IP address with
-this variable. It is still possible to listen on several interfaces at the same
-time though, if they share the same IP address.
+@cindex Interface
+@item Interface = <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.
+Currently this option only affects the Linux tun/tap device.
+
+@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 unicast packets of routable protocols (IPv4 and IPv6) are supported in this mode.
+
+@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.
+
+@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 = <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
+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.
-@item ListenPort = <port> (655)
-Listen on local port port. The computer connecting to this daemon should
-use this number as the argument for his ConnectPort.
+@cindex MACExpire
+@item MACExpire = <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 Name
+@item @strong{Name = <name>}
+This is a symbolic name for this connection. It can be anything
+
+@cindex PingTimeout
+@item PingTimeout = <seconds> (60)
+The number of seconds of inactivity that tinc will wait before sending a
+probe to the other end. If that other end doesn't answer within that
+same amount of seconds, 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.
-@item MyOwnVPNIP = <local address[/maskbits]> (required)
-The local address is the number that the daemon will propagate to
-other daemons on the network when it is identifying itself. Hence this
-will be the file name of the passphrase file that the other end expects
-to find the passphrase in.
+@cindex PrivateKey
+@item PrivateKey = <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.
-The local address is the IP address of the tap device, not the real IP
-address of the host running tincd. Due to changes in recent kernels, it
-is also necessary that you make the ethernet (also known as MAC) address
-equal to the IP address (see the example).
+@cindex PrivateKeyFile
+@item @strong{PrivateKeyFile = <path>} [recommended]
+This is the full path name of the RSA private key file that was
+generated by ``tincd --generate-keys''. It must be a full path, not a
+relative directory.
-maskbits is the number of bits set to 1 in the netmask part.
+Note that there must be exactly one of PrivateKey
+or PrivateKeyFile
+specified in the configuration file.
-@item MyVirtualIP = <local address[/maskbits]>
-This is an alias for MyOwnVPNIP.
+@end table
-@item Passphrases = <directory> (/etc/tinc/NETNAME/passphrases)
-The directory where tinc will look for passphrases when someone tries to
-connect. Please see the manpage for genauth(8) for more information
-about passphrases as used by tinc.
-@item PingTimeout = <seconds> (5)
-The number of seconds of inactivity that tinc will wait before sending a
-probe to the other end. If that other end doesn't answer within that
-same amount of seconds, the connection is terminated, and the others
-will be notified of this.
+@c ==================================================================
+@node Host configuration variables, How to configure, Main configuration variables, Configuration files
+@subsection Host configuration variables
-@item TapDevice = <device> (/dev/tap0)
-The ethertap device to use. Note that you can only use one device per
-daemon. The info pages of the tinc package contain more information
-about configuring an ethertap device for Linux.
-
-@item TCPonly = <yes|no> (no, experimental)
-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. This is experimental code,
-try this at your own risk.
-
-@item VpnMask = <mask> (optional)
-The mask that defines the scope of the entire VPN. This option is not used
-by the tinc daemon itself, but can be used by startup scripts to configure
-the ethertap devices correctly.
+@table @asis
+@cindex Address
+@item @strong{Address = <IP address|hostname>} [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.
+
+@cindex Cipher
+@item Cipher = <cipher> (blowfish)
+The symmetric cipher algorithm used to encrypt UDP packets.
+Any cipher supported by OpenSSL is recognized.
+
+@cindex Compression
+@item Compression = <level> (0)
+This option sets the level of compression used for UDP packets.
+Possible values are 0 (off), 1 (fast) and any integer up to 9 (best).
+
+@cindex Digest
+@item Digest = <digest> (sha1)
+The digest algorithm used to authenticate UDP packets.
+Any digest supported by OpenSSL is recognized.
+Furthermore, specifying "none" will turn off packet authentication.
+
+@cindex IndirectData
+@item IndirectData = <yes|no> (no)
+This option specifies whether other tinc daemons besides the one you
+specified with ConnectTo can make a direct connection to you. This is
+especially useful if you are behind a firewall and it is impossible to
+make a connection from the outside to your tinc daemon. Otherwise, it
+is best to leave this option out or set it to no.
+
+@cindex MACLength
+@item MACLength = <length> (4)
+The length of the message authentication code used to authenticate UDP packets.
+Can be anything from 0
+up to the length of the digest produced by the digest algorithm.
+
+@cindex Port
+@item Port = <port> (655)
+This is the port this tinc daemon listens on.
+You can use decimal portnumbers or symbolic names (as listed in /etc/services).
+
+@cindex PublicKey
+@item PublicKey = <key> [obsolete]
+This is the RSA public key for this host.
+
+@cindex PublicKeyFile
+@item PublicKeyFile = <path> [obsolete]
+This is the full path name of the RSA public key file that was generated
+by ``tincd --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 = <address[/prefixlength]>
+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.
+Shorthand notations are not supported.
+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 fec0:0:0:1:0:0:0:0/64.
+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{ftp://ftp.isi.edu/in-notes/rfc1519.txt, RFC1519}
+
+@cindex TCPonly
+@item TCPonly = <yes|no> (no) [experimental]
+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.
@end table
+@c ==================================================================
+@node How to configure, , Host configuration variables, Configuration files
+@subsection How to configure
+
+@subsubheading Step 1. Creating the main configuration file
+
+The main configuration file will be called @file{/etc/tinc/netname/tinc.conf}.
+Adapt the following example to create a basic configuration file:
+
+@example
+Name = @emph{yourname}
+Device = @emph{/dev/tap0}
+PrivateKeyFile = /etc/tinc/@emph{netname}/rsa_key.priv
+@end example
+
+Then, if you know to which other tinc daemon(s) yours is going to connect,
+add `ConnectTo' values.
+
+@subsubheading Step 2. Creating your host configuration file
+
+If you added a line containing `Name = yourname' in the main configuarion file,
+you will need to create a host configuration file @file{/etc/tinc/netname/hosts/yourname}.
+Adapt the following example to create a host configuration file:
+
+@example
+Address = @emph{your.real.hostname.org}
+Subnet = @emph{192.168.1.0/24}
+@end example
+
+You can also use an IP address instead of a hostname.
+The `Subnet' specifies the address range that is local for @emph{your part of the VPN only}.
+If you have multiple address ranges you can specify more than one `Subnet'.
+You might also need to add a `Port' if you want your tinc daemon to run on a different port number than the default (655).
+
+
+@c ==================================================================
+@node Generating keypairs, Network interfaces, Configuration files, Configuration
+@section Generating keypairs
+
+@cindex key generation
+Now that you have already created the main configuration file and your host configuration file,
+you can easily create a public/private keypair by entering the following command:
+
+@example
+tincd -n @emph{netname} -K
+@end example
+
+tinc will generate a public and a private key and ask you where to put them.
+Just press enter to accept the defaults.
+
+
+@c ==================================================================
+@node Network interfaces, Example configuration, Generating keypairs, Configuration
+@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 `tun0', `tap0', or,
+if you are using the Linux tun/tap driver, the network interface will by default have the same name as the netname.
+
+@cindex tinc-up
+You can configure the network interface by putting ordinary ifconfig, route, and other commands
+to a script named @file{/etc/tinc/netname/tinc-up}. When tinc starts, this script
+will be executed. When tinc exits, it will execute the script named
+@file{/etc/tinc/netname/tinc-down}, but normally you don't need to create that script.
+
+An example @file{tinc-up} script:
+
+@example
+#!/bin/sh
+ifconfig $INTERFACE hw ether fe:fd:0:0:0:0
+ifconfig $INTERFACE 192.168.1.1 netmask 255.255.0.0
+ifconfig $INTERFACE -arp
+@end example
+
+@cindex MAC address
+@cindex hardware address
+The first line sets up the MAC address of the network interface.
+Due to the nature of how Ethernet and tinc work, it has to be set to fe:fd:0:0:0:0
+for tinc to work in it's normal mode.
+If you configured tinc to work in `switch' or `hub' mode, the hardware address should instead
+be set to a unique address instead of fe:fd:0:0:0:0.
+
+You can use the environment variable $INTERFACE to get the name of the interface.
+However, this might not be reliable. If in doubt, use the name of the interface explicitly.
+
+@cindex ifconfig
+The next line gives the interface an IP address and a netmask.
+The kernel will also automatically add a 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.
+
+@cindex arp
+The last line tells the kernel not to use ARP on that interface.
+Again this has to do with how Ethernet and tinc work.
+Use this option only if you are running tinc under Linux and are using tinc's normal routing mode.
+
@c ==================================================================
-@node Example, , Configuration file, Configuring tinc
-@section Example
+@node Example configuration, , Network interfaces, Configuration
+@section Example configuration
-Imagine the following situation. An A-based 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
+@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
@end example
``gateway'' is the VPN IP address of the machine that is running the
-tincd. ``internet IP'' is the IP address of the firewall, which does not
+tincd. ``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&UDP on port
655 (unless otherwise configured).
In this example, it is assumed that eth0 is the interface that points to
-the inner 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.
+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.
+
+@subsubheading For Branch A
-@subsubheading For A
+@emph{BranchA} would be configured like this:
-@emph{A} would be configured like this:
+In @file{/etc/tinc/company/tinc-up}:
@example
-#ifconfig eth0 10.1.54.1 netmask 255.255.0.0 broadcast 10.1.255.255
-ifconfig tap0 hw ether fe:fd:0a:01:36:01
+# Real interface of internal network:
+# ifconfig eth0 10.1.54.1 netmask 255.255.0.0 broadcast 10.1.255.255
+
+ifconfig tap0 hw ether fe:fd:0:0:0:0
ifconfig tap0 10.1.54.1 netmask 255.0.0.0
+ifconfig tap0 -arp
@end example
-and in /etc/tinc/tinc.conf:
+and in @file{/etc/tinc/company/tinc.conf}:
@example
-TapDevice = /dev/tap0
-MyVirtualIP = 10.1.54.1/16
-VpnMask = 255.0.0.0
+Name = BranchA
+PrivateKey = /etc/tinc/company/rsa_key.priv
+Device = /dev/tap0
@end example
-@subsubheading For B
+On all hosts, /etc/tinc/company/hosts/BranchA contains:
@example
-#ifconfig eth0 10.2.43.8 netmask 255.255.0.0 broadcast 10.2.255.255
-ifconfig tap0 hw ether fe:fd:0a:02:01:0c
+Subnet = 10.1.0.0/16
+Address = 1.2.3.4
+
+Note that the IP addresses of eth0 and tap0 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 give both real internal network interfaces and tap interfaces the same IP address,
+since that will make things a lot easier to remember and set up.
+
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
+@end example
+
+
+@subsubheading For Branch B
+
+In @file{/etc/tinc/company/tinc-up}:
+
+@example
+# Real interface of internal network:
+# ifconfig eth0 10.2.43.8 netmask 255.255.0.0 broadcast 10.2.255.255
+
+ifconfig tap0 hw ether fe:fd:0:0:0:0
ifconfig tap0 10.2.1.12 netmask 255.0.0.0
+ifconfig tap0 -arp
@end example
-and in /etc/tinc/tinc.conf:
+and in @file{/etc/tinc/company/tinc.conf}:
@example
-TapDevice = /dev/tap0
-MyVirtualIP = 10.2.1.12/16
-ConnectTo = 1.2.3.4
-VpnMask = 255.0.0.0
+Name = BranchB
+ConnectTo = BranchA
+PrivateKey = /etc/tinc/company/rsa_key.priv
@end example
Note here that the internal address (on eth0) doesn't have to be the
-same as on the tap0 device. Also, ConnectTo is given so that no-one can
+same as on the tap0 device. Also, ConnectTo is given so that no-one can
connect to this node.
-@subsubheading For C
+On all hosts, in @file{/etc/tinc/company/hosts/BranchB}:
@example
-#ifconfig eth0 10.3.69.254 netmask 255.255.0.0 broadcast 10.3.255.255
-ifconfig tap0 hw ether fe:fd:0a:03:45:fe
-ifconfig tap0 10.3.69.254 netmask 255.0.0.0
+Subnet = 10.2.0.0/16
+Address = 2.3.4.5
+
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
@end example
-and in /etc/tinc/A/tinc.conf:
+
+@subsubheading For Branch C
+
+In @file{/etc/tinc/company/tinc-up}:
@example
-MyVirtualIP = 10.3.69.254/16
-TapDevice = /dev/tap1
-ConnectTo = 1.2.3.4
-ListenPort = 2000
-VpnMask = 255.0.0.0
+# Real interface of internal network:
+# ifconfig eth0 10.3.69.254 netmask 255.255.0.0 broadcast 10.3.255.255
+
+ifconfig tap1 hw ether fe:fd:0:0:0:0
+ifconfig tap1 10.3.69.254 netmask 255.0.0.0
+ifconfig tap1 -arp
+@end example
+
+and in @file{/etc/tinc/company/tinc.conf}:
+
+@example
+Name = BranchC
+ConnectTo = BranchA
+Device = /dev/tap1
@end example
C already has another daemon that runs on port 655, so they have to
-reserve another port for tinc. It can connect to other tinc daemons on
-the regular port though, so no ConnectPort variable is needed.
-They also use the netname to distinguish
-between the two. tinc is started with `tincd -n A'.
+reserve another port for tinc. It knows the portnumber it has to listen on
+from it's own host configuration file.
-@subsubheading For D
+On all hosts, in @file{/etc/tinc/company/hosts/BranchC}:
@example
-#ifconfig tap0 10.4.3.32 netmask 255.255.0.0 broadcast 10.4.255.255
-ifconfig tap0 hw ether fe:fd:0a:04:03:20
-ifconfig tap0 10.4.3.32 netmask 255.0.0.0
+Address = 3.4.5.6
+Subnet = 10.3.0.0/16
+Port = 2000
+
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
@end example
-and in /etc/tinc/tinc.conf:
+
+@subsubheading For Branch D
+
+In @file{/etc/tinc/company/tinc-up}:
@example
-MyVirtualIP = 10.4.3.32/16
-ConnectTo = 3.4.5.6
-ConnectPort = 2000
-VpnMask=255.0.0.0
+# Real interface of internal network:
+# ifconfig eth0 10.4.3.32 netmask 255.255.0.0 broadcast 10.4.255.255
+
+ifconfig company hw ether fe:fd:0:0:0:0
+ifconfig company 10.4.3.32 netmask 255.0.0.0
+ifconfig company -arp
@end example
-D will be connecting to C, which has a tincd running for this network on
-port 2000. Hence they need to put in a ConnectPort, but it doesn't need
-to have a different ListenPort.
+and in @file{/etc/tinc/company/tinc.conf}:
+
+@example
+Name = BranchD
+ConnectTo = BranchC
+Device = /dev/net/tun
+PrivateKeyFile = /etc/tinc/company/rsa_key.priv
+@end example
-@subsubheading Authentication
+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.
+Also note that since D uses the tun/tap driver, the network interface
+will not be called `tun' or `tap0' or something like that, but will
+have the same name as netname.
-A, B, C and D all generate a passphrase with genauth 2048, the output is
-stored in /etc/tinc/passphrases/local, except for C, where it should be
-/etc/tinc/A/passphrases/local.
+On all hosts, in @file{/etc/tinc/company/hosts/BranchD}:
-A stores a copy of B's passphrase in /etc/tinc/passphrases/10.2.0.0
+@example
+Subnet = 10.4.0.0/16
+Address = 4.5.6.7
-A stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.0.0
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
+@end example
-B stores a copy of A's passphrase in /etc/tinc/passphrases/10.1.0.0
+@subsubheading Key files
-C stores a copy of A's passphrase in /etc/tinc/A/passphrases/10.1.0.0
+A, B, C and D all have generated a public/private keypair with the following command:
-C stores a copy of D's passphrase in /etc/tinc/A/passphrases/10.4.0.0
+@example
+tincd -n company -K
+@end example
-D stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.0.0
+The private key is stored in @file{/etc/tinc/company/rsa_key.priv},
+the public key is put into the host configuration file in the @file{/etc/tinc/company/hosts/} directory.
+During key generation, tinc automatically guesses the right filenames based on the -n option and
+the Name directive in the @file{tinc.conf} file (if it is available).
@subsubheading Starting
-A has to start their tincd first. Then come B and C, where C has to
-provide the option `-n A', because they have more than one tinc
-network. Finally, D's tincd is started.
-
+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, Technical information, Configuring tinc, Top
+@node Running tinc, Technical information, Configuration, Top
@chapter Running tinc
-Running tinc isn't just as easy as typing `tincd' and hoping everything
-will just work out the way you wanted. Instead, the use of tinc is a
-project that involves trust relations and more than one computer.
+If everything else is done, you can start tinc by typing the following command:
+
+@example
+tincd -n @emph{netname}
+@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
-* Managing keys::
-* Runtime options::
+* Runtime options::
+* Error messages::
@end menu
@c ==================================================================
-@node Managing keys, Runtime options, Running tinc, Running tinc
-@section Managing keys
+@node Runtime options, Error messages, , Running tinc
+@section Runtime options
-Before attempting to start tinc, you have to create passphrases. When
-tinc tries to make a connection, it exchanges some sensitive
-data. Before doing so, it likes to know if the other end is
-trustworthy.
+Besides the settings in the configuration file, tinc also accepts some
+command line options.
-To do this, both ends must have some knowledge about the other. In the
-case of tinc this is the authentication passphrase.
+@cindex command line
+@cindex runtime options
+@cindex options
+@c from the manpage
+@table @samp
+@item --bypass-security
+Disables encryption and authentication.
+Only useful for debugging.
+
+@item -c, --config=PATH
+Read configuration options from the directory PATH. The default is
+@file{/etc/tinc/netname/}.
+
+@cindex debug level
+@item -d, --debug=LEVEL
+Set debug level to LEVEL. The higher the debug level, the more gets
+logged. Everything goes via syslog.
+
+@item -K, --generate-keys[=BITS]
+Generate public/private keypair of BITS length. If BITS is not specified,
+1024 is the default. 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
+in combination with -K). After that, tinc will quit.
-This passphrase is a number, which is chosen at random. This number is
-then sent to the other computers which want to talk to us directly. To
-avoid breaking security, this should be done over a known secure channel
-(such as ssh or similar).
+@item --help
+Display a short reminder of these runtime options and terminate.
-All passphrases are stored in the passphrases directory, which is
-normally /etc/tinc/nn/passphrases/, but it may be changed using the
-`Passphrases' option in the config file.
+@item -k, --kill[=SIGNAL]
+Attempt to kill a running tincd (optionally with the specified SIGNAL instead of SIGTERM) and exit.
+Use it in conjunction with the -n option to make sure you kill the right tinc daemon.
-To generate a passphrase, run `genauth'. genauth takes one argument,
-which is the length of the passphrase in bits. The length of the
-passphrase should be in the range 1024--2048 for a key length of 128
-bits. genauth creates a random number of the specified length, and puts
-it to stdout.
+@item -n, --net=NETNAME
+Connect to net NETNAME. @xref{Multiple networks}.
-Every computer that wants to participate in the VPN should do this, and
-store the output in the passphrases directory, in the file @file{local}.
+@item -D, --no-detach
+Don't fork and detach.
+This will also disable the automatic restart mechanism for fatal errors.
-When every computer has his own local key, it should copy it to the
-computer that it wants to talk to directly. (i.e. the one it connects to
-during startup.) This should be done via a secure channel, because it is
-sensitive information. If this is not done securely, someone might break
-in on you later on.
+@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.
-Those non-local passphrase files must have the name of the VPN IP
-address that they will advertise to you. For instance, if a computer
-tells us it likes to be 10.1.1.3 with netmask 255.255.0.0, the file
-should still be called 10.1.1.3, and not 10.1.0.0.
+@item --version
+Output version information and exit.
+
+@end table
@c ==================================================================
-@node Runtime options, , Managing keys, Running tinc
-@section Runtime options
+@node Error messages, , Runtime options, Running tinc
+@section Error messages
-Besides the settings in the configuration file, tinc also accepts some
-command line options.
+What follows is a list of the most common error messages you can see
+when configuring tinc. Most of these messages are visible in the syslog
+only, so keep an eye on it!
-This list is a longer version of that in the manpage. The latter is
-generated automatically, so may be more up-to-date.
+@table @strong
+@item Could not open /dev/tap0: No such device
-@c from the manpage
-@table @asis
-@item -c, --config=FILE
-Read configuration options from FILE. The default is
-@file{/etc/tinc/nn/tinc.conf}.
+@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 -d
-Increase debug level. The higher it gets, the more gets
-logged. Everything goes via syslog.
+@item Can't write to /dev/net/tun: No such device
-0 is the default, only some basic information connection attempts get
-logged. Setting it to 1 will log a bit more, still not very
-disturbing. With two -d's tincd will log protocol information, which can
-get pretty noisy. Three or more -d's will output every single packet
-that goes out or comes in, which probably generates more data than the
-packets themselves.
+@itemize
+@item You forgot to `modprobe tun'.
+@item You forgot to compile `Universal TUN/TAP driver' in the kernel.
+@end itemize
-@item -k, --kill
-Attempt to kill a running tincd and exit. A TERM signal (15) gets sent
-to the daemon that his its PID in /var/run/tinc.nn.pid.
+@item Packet with destination 1.2.3.4 is looping back to us!
-Because it kills only one tincd, you should use -n here if you use it
-normally.
+@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 `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 -n, --net=NETNAME
-Connect to net NETNAME. @xref{Multiple networks}.
+@item Network doesn't work, syslog shows only packets of length 46
-@item -t, --timeout=TIMEOUT
-Seconds to wait before giving a timeout. Should not be set too low,
-because every time tincd senses a timeout, it disconnects and reconnects
-again, which will cause unnecessary network traffic and log messages.
+@item Network address and prefix length do not match!
-@item --help
-Display a short reminder of these runtime options and terminate.
+@itemize
+@item The Subnet field must contain a @emph{network} address.
+@item If you only want to use one IP address, set the netmask to /32.
+@end itemize
-@item --version
-Output version information and exit.
+@item This is a bug: net.c:253: 24: Some error
-@end table
+@itemize
+@item This is something that should not have happened.
+Please report this, and tell us exactly what went wrong before you got
+this message. In normal operation, these errors should not occur.
+@end itemize
+
+@item Error reading RSA key file `rsa_key.priv': No such file or directory
+@itemize
+@item You must specify the complete pathname.
+Specifying a relative path does not make sense here. tinc changes its
+directory to / when starting (to avoid keeping a mount point busy).
+@end itemize
+
+@end table
@c ==================================================================
@node Technical information, About us, Running tinc, Top
@chapter Technical information
-@c ==================================================================
@menu
-* The Connection::
-* Security::
+* The connection::
+* The meta-protocol::
+* Security::
@end menu
-@node The Connection, Security, Technical information, Technical information
-@section The basic philosophy of the way tinc works
-@cindex Connection
+@c ==================================================================
+@node The connection, The meta-protocol, Technical information, Technical information
+@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
-* Protocol Preview::
-* The Meta-connection::
+* The UDP tunnel::
+* The meta-connection::
@end menu
@c ==================================================================
-@node Protocol Preview, The Meta-connection, The Connection, The Connection
-@subsection A preview of the way the tinc works
+@node The UDP tunnel, The meta-connection, The connection, The connection
+@subsection The UDP tunnel
-@cindex ethertap
+@cindex virtual network device
@cindex frame type
The data itself is read from a character device file, the so-called
-@emph{ethertap} 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. Data to
-and from the device is formatted as if it were a normal ethernet card,
+@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. Data to
+and from the device is formatted as if it were a normal Ethernet card,
so a frame is preceded by two MAC addresses and a @emph{frame type}
field.
-So when tinc reads an ethernet frame from the device, it determines its
-type. Right now, tinc can only handle Internet Protocol version 4 (IPv4)
-frames. Plans to support other protocols are being made. When tinc knows
-which type of frame it has read, it can also read the source and
-destination address from it.
+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.
+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).
-Now it is time that the frame gets encrypted. Currently the only
-encryption algorithm available is blowfish.
+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
-When the encryption is ready, 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
+@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 does a decrypt on the contents of the UDP datagram,
-and it writes the decrypted information to its own ethertap device.
+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.
+
+To let the kernel on the receiving end accept the packet, 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 cannot be set
+by the sending daemons.
+tinc solves this by letting the receiving end detect the MAC address
+and overwriting the destination MAC address of the received packet.
+However, the MAC address of the network interface at the receiver might not always be known to tinc.
+That is the reason why you should set the MAC address of your tap interface to that address
+when in routing mode.
+
+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.
@c ==================================================================
-@node The Meta-connection, , Protocol Preview, The Connection
+@node The meta-connection, , The UDP tunnel, The connection
@subsection The meta-connection
-Having only an UDP connection available is not enough. Though suitable
+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 encryption information to somebody.
+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
+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, an how he should react. Because we
-have two connections, we also have two protocols. The protocol used for
+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
+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 ACK's sent instead of just one. Furthermore, if 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 resending packets.
+start re-sending packets.
+
+
+@c ==================================================================
+@node The meta-protocol, Security, The connection, Technical information
+@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{Authentication protocol}. 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
+daemon message
+--------------------------------------------------------------------------
+origin 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
+
+origin 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, , The Connection, Technical information
+@node Security, , The meta-protocol, Technical information
@section About tinc's encryption and other security-related issues.
-@cindex tinc
+@cindex TINC
@cindex Cabal
tinc got its name from ``TINC,'' short for @emph{There Is No Cabal}; the
-alleged Cabal was/is an organization that was said to keep an eye on the
-entire Internet. As this is exactly what you @emph{don't} want, we named
+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
+your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does
exactly that: encrypt.
-
-This chapter is a mixture of ideas, reasoning and explanation, please
-don't take it too serious.
+tinc by default uses blowfish encryption with 128 bit keys in CBC mode, 32 bit
+sequence numbers and 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.
@menu
-* Key Types::
-* Key Management::
-* Authentication::
-* Protection::
+* Authentication protocol::
+* Encryption of network packets::
@end menu
-@c ==================================================================
-@node Key Types, Key Management, Security, Security
-@subsection Key Types
-@c FIXME: check if I'm not talking nonsense
-
-There are several types of encryption keys. Tinc uses two of them,
-symmetric private keypairs and public/private keypairs.
-
-Public/private keypairs are used in public key cryptography. It enables
-someone to send out a public key with which other people can encrypt their
-data. The encrypted data now can only be decrypted by the person who has
-the private key that matches the public key. So, a public key only allows
-@emph{other} people to send encrypted messages to you. This is very useful
-in setting up private communications channels. Just send out your public key
-and other people can talk to you in a secure way. But how can you know
-the other person is who he says he is?
-
-For authentication itself tinc uses symmetric private keypairs, referred
-to as a passphrase. The identity of each tinc daemon is defined by it's
-passphrase (like you can be identified by your social security number).
-Every tinc daemon that is allowed to connect to you has a copy of your
-passphrase (hence symmetrical).
-
-It would also be possible to use public/private keypairs for authentication,
-so that you could shout out your public key and don't need to keep it
-secret (like the passphrase you would have to send to someone else). Also,
-no one else has to know a private key from you.
-Both forms have their pros and cons, and at the moment tinc just uses passphrases
-(which are computationaly more efficient and perhaps in some way more
-secure).
@c ==================================================================
-@node Key Management, Authentication, Key Types, Security
-@subsection Key Management
-@c FIXME: recheck
-@c I did, it sounds sane :) [guus]
+@node Authentication protocol, Encryption of network packets, Security, Security
+@subsection Authentication protocol
+
+@cindex authentication
+A new scheme for authentication in tinc has been devised, which offers some
+improvements over the protocol used in 1.0pre2 and 1.0pre3. Explanation is
+below.
+
+@cindex ID
+@cindex META_KEY
+@cindex CHALLENGE
+@cindex CHAL_REPLY
+@cindex ACK
+@example
+daemon message
+--------------------------------------------------------------------------
+client <attempts connection>
-@cindex Diffie-Hellman
-You can't just send a private encryption key to your peer, because
-somebody else might already be listening to you. So you'll have to
-negotiate over a shared but secret key. One way to do this is by using
-the ``Diffie-Hellman key exchange'' protocol
-(@uref{http://www.rsa.com/rsalabs/faq/html/3-6-1.html}). The idea is as
-follows.
+server <accepts connection>
-You have two participants A and B that want to agree over a shared
-secret encryption key. Both parties have some large prime number p and a
-generator g. These numbers may be known to the outside world, and hence
-may be included in the source distribution.
+client ID client 12
+ | +---> version
+ +-------> name of tinc daemon
-@cindex secret key
-Both parties then generate a secret key. A generates a, and computes g^a
-mod p. This is then sent to B; while B computes g^b mod p, and transmits
-this to A, b being generated by B. Both a and b must be smaller than
-p-1.
+server ID server 12
+ | +---> version
+ +-------> name of tinc daemon
-Both parties then calculate g^ab mod p = k. k is the new, shared, but
-still secret key.
+client META_KEY 5f0823a93e35b69e...7086ec7866ce582b
+ \_________________________________/
+ +-> RSAKEYLEN bits totally random string S1,
+ encrypted with server's public RSA key
-To obtain a key k of a sufficient length (128 bits in our vpnd), p
-should be 2^129-1 or more.
+server META_KEY 6ab9c1640388f8f0...45d1a07f8a672630
+ \_________________________________/
+ +-> RSAKEYLEN bits totally random string S2,
+ encrypted with client's public RSA key
+From now on:
+ - the client will symmetrically encrypt outgoing traffic using S1
+ - the server will symmetrically encrypt outgoing traffic using S2
-@c ==================================================================
-@node Authentication, Protection, Key Management, Security
-@subsection Authentication
-@c FIXME: recheck
-
-@cindex man-in-the-middle attack
-Because the Diffie-Hellman protocol is in itself vulnerable to the
-``man-in-the-middle attack,'' we should introduce an authentication
-system.
-
-We will let A transmit a passphrase that is also known to B encrypted
-with g^a, before A sends this to B. This way, B can check whether A is
-really A or just someone else.
-B will never receive the real passphrase though, because it was
-encrypted using public/private keypairs. This way there is no way an
-imposter could steal A's passphrase.
-
-@cindex passphrase
-@c ehrmz... but we only use 1024 bits passphrases ourselves? [guus]
-This passphrase should be 2304 bits for a symmetric encryption
-system. But since an asymmetric system is more secure, we could do with
-2048 bits. This only holds if the passphrase is very random.
-
-These passphrases could be stored in a file that is non-readable by
-anyone else but root; e.g. @file{/etc/tinc/passphrases} with UID 0
-and permissions mode 700.
-
-The only thing that needs to be taken care of is how A can securely send
-a copy of it's passphrase to B if B doesn't have it yet. This could be
-done via mail with PGP, but you should be really convinced of the
-identity of the person who owns the email address you are sending this to.
-Swapping floppy disks in real life might be the best way to do this!
+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 new scheme has several improvements, both in efficiency and security.
+
+First of all, the server sends exactly the same kind of messages over the wire
+as the client. The previous versions of tinc first authenticated the client,
+and then the server. This scheme even allows both sides to send their messages
+simultaneously, there is no need to wait for the other to send something first.
+This means that any calculations that need to be done upon sending or receiving
+a message can also be done in parallel. This is especially important when doing
+RSA encryption/decryption. Given that these calculations are the main part of
+the CPU time spent for the authentication, speed is improved by a factor 2.
+
+Second, only one RSA encrypted message is sent instead of two. This reduces the
+amount of information attackers can see (and thus use for a cryptographic
+attack). It also improves speed by a factor two, making the total speedup a
+factor 4.
+
+Third, and most important:
+The symmetric cipher keys are exchanged first, the challenge is done
+afterwards. In the previous authentication scheme, because a man-in-the-middle
+could pass the challenge/chal_reply phase (by just copying the messages between
+the two real tinc daemons), but no information was exchanged that was really
+needed to read the rest of the messages, the challenge/chal_reply phase was of
+no real use. The man-in-the-middle was only stopped by the fact that only after
+the ACK messages were encrypted with the symmetric cipher. Potentially, it
+could even send it's own symmetric key to the server (if it knew the server's
+public key) and read some of the metadata the server would send it (it was
+impossible for the mitm to read actual network packets though). The new scheme
+however prevents this.
+
+This new scheme makes sure that first of all, symmetric keys are exchanged. The
+rest of the messages are then encrypted with the symmetric cipher. Then, each
+side can only read received messages if they have their private key. The
+challenge is there to let the other side know that the private key is really
+known, because a challenge reply can only be sent back if the challenge is
+decrypted correctly, and that can only be done with knowledge of the private
+key.
+
+Fourth: the first thing that is send via the symmetric cipher encrypted
+connection is a totally random string, so that there is no known plaintext (for
+an attacker) in the beginning of the encrypted stream.
@c ==================================================================
-@node Protection, , Authentication, Security
-@subsection Protecting your data
+@node Encryption of network packets, , Authentication protocol, Security
+@subsection Encryption of network packet
+@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. The packet is stored in a queue while waiting for the
+key to arrive.
+
+@cindex UDP
+The UDP packet containing the network packet from the VPN has the following layout:
-Now we have securely hidden our data. But a malicious cracker may still
-bother you by randomly altering the encrypted data he intercepts.
+@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. By default the
+first 4 bytes of the digest are used for this, but this can be changed using
+the MACLength configuration variable.
@c ==================================================================
@node About us, Concept Index, Technical information, Top
@menu
-* Contact Information::
-* Authors::
+* Contact Information::
+* Authors::
@end menu
@node Contact Information, Authors, About us, About us
@section Contact information
-tinc's main page is at @url{http://tinc.nl.linux.org/},
+@cindex website
+tinc's website is at @url{http://tinc.nl.linux.org/},
this server is located in the Netherlands.
-We have an IRC channel on the Open Projects IRC network. Connect to
-@uref{http://openprojects.nu/services/irc.html, irc.openprojects.net},
+@cindex IRC
+We have an IRC channel on the FreeNode IRC network. Connect to
+@uref{http://www.freenode.net/, irc.freenode.net}
and join channel #tinc.
@section Authors
@table @asis
-@item Ivo Timmermans (zarq) (@email{itimmermans@@bigfoot.com})
-Main coder/hacker and maintainer of the package.
-
-@item Guus Sliepen (guus)
-Originator of it all, co-author.
-
-@item Wessel Dankers (Ubiq)
-General obfuscater of the code.
-
+@item Ivo Timmermans (zarq) (@email{ivo@@o2w.nl})
+@item Guus Sliepen (guus) (@email{guus@@sliepen.eu.org})
@end table
-Thank you's to: Dekan, Emphyrio, vDong
-
-Greetings to: braque, Fluor, giggles, macro, smoke, tribbel
+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 ==================================================================
@c ==================================================================
@contents
@bye
-
projects / tinc / blobdiff