\input texinfo @c -*-texinfo-*-
+@c $Id: tinc.texi,v 1.9 2000/10/18 20:12:06 zarq Exp $
@c %**start of header
@setfilename tinc.info
@settitle tinc Manual
This is the info manual for tinc, a Virtual Private Network daemon.
-Copyright 1998,199,2000 Ivo Timmermans <itimmermans@@bigfoot.com>
+Copyright @copyright{} 1998,199,2000 Ivo Timmermans
+<itimmermans@@bigfoot.com>, Guus Sliepen <guus@@sliepen.warande.net> 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 1.9 2000/10/18 20:12:06 zarq 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>
+@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{} 1998,1999,2000 Ivo Timmermans
+<itimmermans@@bigfoot.com>, Guus Sliepen <guus@@sliepen.warande.net> and
+Wessel Dankers <wsl@@nl.linux.org>.
+
+$Id: tinc.texi,v 1.9 2000/10/18 20:12:06 zarq 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::
+* Installing tinc - preparations::
+* Installing tinc - installation::
* Configuring tinc::
* Running tinc::
* Technical information::
* Concept Index:: All used terms explained
@end menu
+
+@contents
+
@c ==================================================================
-@node Introduction, Configuring a Linux system, Top, Top
+@node Introduction, Installing tinc - 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.
@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
more than just one way.
@cindex private
-For instance, a VPN can consist of a single stand-alone ethernet LAN. Or
-even two computers hooked up using a null-modem cable@footnote{Though
-discuss-able, I think it qualifies as a VPN.}. In these cases, it is
-obvious that the network is @emph{private}. But there is another type
-of VPN, the type tinc was made for.
+Private networks can consist of a single stand-alone ethernet LAN. Or
+even two computers hooked up using a null-modem cable. In these cases,
+it is
+obvious that the network is @emph{private}, no one can access it from the
+outside. But if your computers are linked to the internet, the network
+is not private anymore, unless one uses firewalls to block all private
+traffic. But then, there is no way to send private data to trusted
+computers on the other end of the internet.
+
+@cindex virtual
+This problem can be solved by using @emph{virtual} networks. Virtual
+networks can live on top of other networks, but 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
+by using firewalls, because the traffic that flows through it has to go
+through the internet, where other people can look at it.
+
+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
@c ==================================================================
-@node tinc, , VPNs, Introduction
+@node tinc, Supported platforms, VPNs, Introduction
@section tinc
+@cindex vpnd
+@cindex ethertap
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
@c ==================================================================
-@node Configuring a Linux system, Installing tinc, Introduction, Top
-@chapter Configuring a Linux system
+@node Supported platforms, , tinc, Introduction
+@section Supported platforms
+
+tinc works on Linux, FreeBSD and Solaris. These are the three platforms
+that are supported by the universial TUN/TAP device driver, so if
+support for other operating systems is added to this driver, perhaps
+tinc will run on them as well. Without this driver, tinc will most
+likely compile and run, but it will not be able to send or receive data
+packets.
+
+@c ==================================================================
+@subsection 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. Take care however, we haven't been able
+to really test it yet. If you want to run tinc on another platform than
+x86, and want to tell us how it went, please do so.
+
+tinc uses the ethertap device that is provided in the standard kernel
+since version 2.1.60, so anything above that (2.2.x, 2.3.x, and the
+2.4.0-testx (which is current at the time of this writing) kernel
+versions) is able to support tinc.
+
+
+@c ==================================================================
+@subsection FreeBSD
+
+tinc on FreeBSD relies on the universial TUN/TAP driver for its data
+acquisition from the kernel. Therefore, tinc suports the same platforms
+as this driver. These are: FreeBSD 3.x, 4.x, 5.x.
+
+
+@c ==================================================================
+@subsection Solaris
+
+tinc on Solaris relies on the universial TUN/TAP driver for its data
+acquisition from the kernel. Therefore, tinc suports the same platforms
+as this driver. These are: Solaris, 2.1.x.
+
+
+@c
+@c
+@c
+@c
+@c
+@c
+@c Preparing your system
+@c
+@c
+@c
+@c
+@c
-This chapter contains information on how a Linux system is configured
-for the use of tinc.
+@c ==================================================================
+@node Installing tinc - preparations, Installing tinc - installation, Introduction, Top
+@chapter Installing tinc: preparations
+
+This chapter contains information on how to prepare your system to
+support tinc.
@menu
* Configuring the kernel::
-* Files Needed::
-* Setting up the devices::
+* Libraries::
@end menu
@c ==================================================================
-@node Configuring the kernel, Files Needed, Configuring a Linux system, Configuring a Linux system
+@node Configuring the kernel, Libraries, Installing tinc - preparations, Installing tinc - preparations
@section Configuring the kernel
+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'. You need both these devices.
+
+If you can install these devices in a similar manner, you may skip this
+section.
+
+@menu
+* Configuration of the Linux kernel::
+* Configuration of the FreeBSD kernel::
+* Configuration of the Solaris kernel::
+@end menu
+
+
+@c ==================================================================
+@node Configuration of the Linux kernel, Configuration of the FreeBSD kernel, Configuring the kernel, Configuring the kernel
+@subsection Configuring the Linux 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
@uref{http://howto.linuxberg.com/LDP/HOWTO/Kernel-HOWTO.html, Kernel
HOWTO} first. Do that now!
-Here are the options you have to turn on/off when configuring a new
+Here are the options you have to turn on when configuring a new
kernel.
+For kernel 2.2.x:
+
@example
Code maturity level options
[*] Prompt for development and/or incomplete code/drivers
<*> Ethertap network tap
@end example
+For kernel 2.3.x and 2.4.x:
+
+@example
+Code maturity level options
+[*] Prompt for development and/or incomplete code/drivers
+Networking options
+[*] Kernel/User netlink socket
+<*> Netlink device emulation
+Network device support
+<*> Universal TUN/TAP device driver support
+@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}.
alias char-major-36 netlink_dev
@end example
+If you have a 2.4 kernel, you can also choose to use the `Ethertap
+network tap' device. This is marked obsolete, because the universal
+TUN/TAP driver is a newer implementation that is supposed to be used in
+favor of ethertap. For tinc, it doesn't really matter which one you
+choose; based on the device file name, tinc will make the right choice
+about what protocol to use.
+
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.
+it. Unfortunately it's not possible to insert these modules in a
+running kernel.
+
+
+@c ==================================================================
+@node Configuration of the FreeBSD kernel, Configuration of the Solaris kernel, Configuration of the Linux kernel, Configuring the kernel
+@subsection Configuring the FreeBSD kernel
+
+This section will contain information on how to configure your FreeBSD
+kernel to support the universal TUN/TAP device. For 5.0 and 4.1
+systems, this is included in the kernel configuration, for earlier
+systems (4.0 and 3.x), you need to install the universal TUN/TAP driver
+yourself.
+
+Unfortunately somebody still has to write the text.
+
+
+@c ==================================================================
+@node Configuration of the Solaris kernel, , Configuration of the FreeBSD kernel, Configuring the kernel
+@subsection Configuring the Solaris kernel
+
+This section will contain information on how to configure your Solaris
+kernel to support the universal TUN/TAP device. You need to install
+this driver yourself.
+
+Unfortunately somebody still has to write the text.
+
+
+@c ==================================================================
+@node Libraries, , Configuring the kernel, Installing tinc - preparations
+@section Libraries
+
+@cindex requirements
+Before you can configure or build tinc, you need to have the OpenSSL
+library installed on your system. If you try to configure tinc without
+having installed it, configure will give you an error message, and stop.
+
+@menu
+* OpenSSL::
+@end menu
+
+
+@c ==================================================================
+@node OpenSSL, , Libraries, Libraries
+@subsection OpenSSL
+
+@cindex OpenSSL
+For all cryptography-related functions, tinc uses the functions provided
+by the OpenSSL library. We recommend using version 0.9.5 or 0.9.6 of
+this library. Other versions may also work, but we can guarantee
+nothing.
+
+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).
+
+
+@c
+@c
+@c
+@c Installing tinc
+@c
+@c
+@c
+@c
+
+@c ==================================================================
+@node Installing tinc - installation, Configuring tinc, Installing tinc - preparations, Top
+@chapter Installing tinc: installation
+
+If you use Redhat or 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 don't run either of these systems, 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 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'.
+
+More detailed instructions are in the file @file{INSTALL}, which is
+included in the source distribution.
+
+@menu
+* Building tinc::
+* System files::
+* Interfaces::
+@end menu
@c ==================================================================
-@node Files Needed, Setting up the devices, Configuring the kernel, Configuring a Linux system
-@section Files Needed
+@node Building tinc, System files, Installing tinc - installation, Installing tinc - installation
+@section Building tinc
-@subsubheading Device files
+Detailed instructions on configuring the source and building tinc can be
+found in the file called @file{INSTALL}.
+
+
+@c ==================================================================
+@node System files, Interfaces, Building tinc, Installing tinc - installation
+@section System files
+
+Before you can run tinc, you
+
+@menu
+* Device files::
+* Other files::
+@end menu
+
+
+@c ==================================================================
+@node Device files, Other files, System files, System files
+@subsection Device files
First, you'll need the special device file(s) that form the interface
between the kernel and the daemon.
+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 the universal TUN/TAP driver, you have to create the
+following device files (unless they already exist):
+
+@example
+mknod -m 600 /dev/... c .. ..
+chown 0.0 /dev/...
+@end example
+
+If you want to have more devices, the device numbers will be .. .. ...
+
+If you use Linux, and you run the new 2.4 kernel using the devfs
+filesystem, then the tap device will be automatically generated as
+@file{/dev/netlink/tap0}.
+
+If you use Linux and have kernel 2.2.x, you have to make the ethertap
+devices:
+
@example
mknod -m 600 /dev/tap0 c 36 16
chown 0.0 /dev/tap0
@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.
+Any further ethertap devices have minor device number 16 through 31.
-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.
+@c ==================================================================
+@node Other files, , Device files, System files
+@subsection Other files
@subsubheading @file{/etc/networks}
myvpn 10.0.0.0
@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.
@subsubheading @file{/etc/services}
@c ==================================================================
-@node Setting up the devices, , Files Needed, Configuring a Linux system
-@section Setting up the devices
+@node Interfaces, , System files, Installing tinc - installation
+@section Interfaces
Before you can start transmitting data over the tinc tunnel, you must
set up the ethertap network devices.
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
+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
ifconfig tap@emph{n} hw ether fe:fd:@emph{xx}:@emph{xx}:@emph{xx}:@emph{xx}
@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
+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 MyOwnVPNIP.
+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).
+
+@cindex MAC address
+@cindex hardware address
+@strong{Tip}: for finding out what the MAC address of the tap interface
+should be, you can use the following command:
@example
-ifconfig tap@emph{n} @emph{IP} netmask @emph{mask}
+$ printf 'fe:fd:%02x:%02x:%02x:%02x' 10 1 54 1
+fe:fd:0a:01:36:01
@end example
-This will activate the device with an IP address @emph{IP} with network
-mask @emph{mask}.
-
+@cindex ifconfig
+To activate the device, you have to assign an IP address to it. To set
+an IP address @emph{IP} with network mask @emph{mask}, do the following:
+@example
+ifconfig tap@emph{n} @emph{xx}.@emph{xx}.@emph{xx}.@emph{xx} netmask @emph{mask}
+@end example
-@c ==================================================================
-@node Installing tinc, Configuring tinc, Configuring a Linux system, Top
-@chapter Installing tinc
-
-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.
+@cindex netmask
+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.
-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'.
-More detailed instructions are in the file @file{INSTALL}, which is
-included in the source distribution.
+@c
+@c
+@c
+@c
+@c Configuring tinc
+@c
+@c
+@c
+@c
@c ==================================================================
-@node Configuring tinc, Running tinc, Installing tinc, Top
+@node Configuring tinc, Running tinc, Installing tinc - installation, Top
@chapter Configuring tinc
@menu
* Example::
@end menu
-
@c ==================================================================
@node Multiple networks, How connections work, Configuring tinc, Configuring tinc
@section Multiple networks
@node Variables, , Configuration file, Configuration file
@subsection Variables
-Here are all valid variables, listed in alphabetical order:
+Here are all valid variables, listed in alphabetical order. The default
+value, required or optional is given between parentheses.
@c straight from the manpage
@table @asis
-@item AllowConnect = (yes|no)
-If set to yes, anyone may try to connect to you. If you set this to no,
-no incoming connections will be accepted. This does not affect the
-outgoing connections.
-
-@item ConnectPort = port
+@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)
-Specifies which host to connect to on startup. If the ConnectPort
-variable is omitted, then tinc will try to connect to port 655.
+@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. Only the initiator of a
-tinc VPN should need this.
-
-@item ListenPort = port
+instead just listen for incoming connections.
+
+@item Hostnames = <yes|no> (no)
+This option selects whether IP addresses (both real and on the VPN) should
+be resolved. Since DNS lookups are blocking, it might affect tinc's
+efficiency, even stopping the daemon for a few seconds everytime it does
+a lookup if your DNS server is not responding.
+
+This does not affect resolving hostnames to IP addresses from the configuration
+file.
+
+@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.
+
+@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
+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. Again, the
-default is 655.
+use this number as the argument for his ConnectPort.
-@item MyOwnVPNIP = local address[/maskbits]
+@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
maskbits is the number of bits set to 1 in the netmask part.
-@item MyVirtualIP = local address[/maskbits]
+@item MyVirtualIP = <local address[/maskbits]>
This is an alias for MyOwnVPNIP.
-@item Passphrases = directory
+@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 = number
+@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.
-@item TapDevice = device
+@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.
@end table
+
@c ==================================================================
@node Example, , Configuration file, Configuring tinc
@section Example
+
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.
655 (unless otherwise configured).
In this example, it is assumed that eth0 is the interface that points to
-the inner LAN of the office. This could be the same as the interface
-that leads to the internet.
+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.
@subsubheading For A
@emph{A} would be configured like this:
@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
ifconfig tap0 10.1.54.1 netmask 255.0.0.0
-ifconfig eth0 10.1.54.1 netmask 255.255.0.0 broadcast 10.1.255.255
@end example
and in /etc/tinc/tinc.conf:
@example
TapDevice = /dev/tap0
MyVirtualIP = 10.1.54.1/16
+VpnMask = 255.0.0.0
@end example
@subsubheading For B
@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
ifconfig tap0 10.2.1.12 netmask 255.0.0.0
-ifconfig eth0 10.2.43.8 netmask 255.255.0.0 broadcast 10.2.255.255
@end example
and in /etc/tinc/tinc.conf:
TapDevice = /dev/tap0
MyVirtualIP = 10.2.1.12/16
ConnectTo = 1.2.3.4
-AllowConnect = no
+VpnMask = 255.0.0.0
@end example
Note here that the internal address (on eth0) doesn't have to be the
@subsubheading For C
@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
-ifconfig eth0 10.3.69.254 netmask 255.255.0.0 broadcast 10.3.255.255
@end example
and in /etc/tinc/A/tinc.conf:
@example
MyVirtualIP = 10.3.69.254/16
+TapDevice = /dev/tap1
ConnectTo = 1.2.3.4
ListenPort = 2000
+VpnMask = 255.0.0.0
@end example
C already has another daemon that runs on port 655, so they have to
-reserve another port for tinc. They also use the netname to distinguish
+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'.
@subsubheading For D
@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
-ifconfig tap0 10.4.3.32 netmask 255.255.0.0 broadcast 10.4.255.255
@end example
and in /etc/tinc/tinc.conf:
MyVirtualIP = 10.4.3.32/16
ConnectTo = 3.4.5.6
ConnectPort = 2000
-AllowConnect = no
+VpnMask=255.0.0.0
@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.
+port 2000. Hence they need to put in a ConnectPort, but it doesn't need
+to have a different ListenPort.
@subsubheading Authentication
stored in /etc/tinc/passphrases/local, except for C, where it should be
/etc/tinc/A/passphrases/local.
-A stores a copy of B's passphrase in /etc/tinc/passphrases/10.2.0.0
+A stores a copy of B's passphrase in /etc/tinc/passphrases/10.2.1.12
-A stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.0.0
+A stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.69.254
-B stores a copy of A's passphrase in /etc/tinc/passphrases/10.1.0.0
+B stores a copy of A's passphrase in /etc/tinc/passphrases/10.1.54.1
-C stores a copy of A's passphrase in /etc/tinc/A/passphrases/10.1.0.0
+C stores a copy of A's passphrase in /etc/tinc/A/passphrases/10.1.54.1
-C stores a copy of D's passphrase in /etc/tinc/A/passphrases/10.4.0.0
+C stores a copy of D's passphrase in /etc/tinc/A/passphrases/10.4.3.32
-D stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.0.0
+D stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.69.254
@subsubheading Starting
@node The Meta-connection, , Protocol Preview, The Connection
@subsection The meta-connection
-Having only a UDP connection available is not enough. Though suitable
+Having only an 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.
don't take it too serious.
@menu
+* Key Types::
* Key Management::
* Authentication::
* Protection::
@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, Security, Security
+@node Key Management, Authentication, Key Types, Security
@subsection Key Management
-@c FIXME: recheck
+@c FIXME change for the current protocol
@cindex Diffie-Hellman
You can't just send a private encryption key to your peer, because
this to A, b being generated by B. Both a and b must be smaller than
p-1.
-These private keys are generated upon startup, and they are not changed
-while the connection exists. A possible feature in the future is to
-dynamically change the keys, every hour for example.
-
Both parties then calculate g^ab mod p = k. k is the new, shared, but
still secret key.
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/vpn/passphrases}.
+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 announces its
-passphrase to B.
+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!
@c ==================================================================
Now we have securely hidden our data. But a malicious cracker may still
bother you by randomly altering the encrypted data he intercepts.
+@c FIXME what the hell is this all about? remove? IT
@c ==================================================================
@node About us, Concept Index, Technical information, Top
projects / tinc / blobdiff