+++ /dev/null
- ==============
- The TINC HOWTO
- ==============
-
- Wessel Dankers
- wsl@nl.linux.org
-\f
-Introduction
-------------
-Tinc is a system to create a virtual ethernet network on top of an existing
-infrastructure. This infrastructure can be anything from modem lines to
-gigabit ethernet networks, as long as they talk IP. Once you install and
-configure tinc, your host will get an extra IP address, just like it would
-when you stick an extra ethernet card into it. Using this IP address, it can
-communicate with all hosts in its virtual network using strong encryption.
-
-If you install Tinc on a router (and pick your numbers correctly) you can
-have the router forward all packets. This way you can---instead of
-connecting hosts---connect entire sites together! Now you need only one
-outgoing network connection for both internet and intranet.
-\f
-Architecture
-------------
-When a few Tinc daemons are running they will try to seek contact with
-eachother. A daemon is all the time connected to a few other daemons,
-but if traffic is required with a daemon it doesn't know yet, it will
-instantly contact it and exchange keys. These so-called meta-connections
-are made over TCP, using encryption of course.
-
-When actual traffic has to be sent, a daemon checks his connection list to
-see if the addressee is known (and makes contact with it if neccessary).
-All packets are then sent using UDP to the other host, just like in a real
-network. If a packet gets lost, the connection layer of Linux will resend
-the packet, just like it would over a normal network.
-
-Once in a while the daemons will renegotiate keys so that even if a cracker
-breaks one, it'll be of limited use.
-\f
-Getting Tinc
-------------
-Before you fetch the latest tarball, you might want to check if there's a
-package for your Linux distribution. One of the main authors is a Debian
-Developer, so you can expect the Debian packages to be very up to date.
-
-The official website for Tinc can be found at http://tinc.nl.linux.org/.
-There you can find Debian packages, RPM's and of course... the tarball!
-Since we run Doohickey Linux Pro 1.0, for which no package exists (or
-indeed the distribution itself) we shall compile the package ourselves.
-\f
-Building
---------
-The Tinc source adheres to so many standards it makes you head spin.
-Even the debug messages have been localized! Amazing. Tinc also comes
-with a configuration script. If you like to see what is there to
-configure run ./configure --help | more. If you don't have time for such
-nonsense:
-
- ./configure --sysconfdir=/etc
-
-This will see if your system is nice enough to run tinc on, and will
-create some Makefiles and other stuff which will together build tinc.
-
- make
- make install
-
-The first will do the actual build, the second copies all files into place.
-\f
-The kernel
-----------
-Next you will have to configure the kernel to support the tap device.
-It is important that you run a recent kernel, but anything after 2.2.16
-will do. You have to enable both the netlink device AND the ethertap
-device (in that order). Enable them as modules!
-Compile, install =) You don't even have to reboot.
-\f
-Picking your numbers
---------------------
-The first thing we should do is pick network numbers. Tinc has a very
-peculiar taste for network numbers, which is caused by the way it routes
-traffic. However, it turns out to be really handy if you want to use
-your tinc host as a router for a site.
-
-The numbers have to be in a range that is not yet in use in your existing,
-real network! In this example we will use numbers from the 192.168.0/16
-range. This is standard CIDR notation for all IP addresses from 192.168.0.0
-to 192.168.255.255. The /16 means that the first 16 bits form the network
-part.
-
-It is common practice for Tinc networks to use private (RFC 1918) addresses.
-This is not necessary, but it would be a waste to use official addresses
-for a private network!
-
-In the example we will connect three machines: f00f, fdiv and hlt. We will
-give each an address, but not just that, also a slice of our address space
-to play with.
-
- Host Real address Tinc network
- ---------------------------------------------------
- f00f 126.202.37.20 192.168.1.1/24
- fdiv 126.202.37.81 192.168.2.1/24
- hlt 103.22.1.218 192.168.3.1/24
-
-It is very important that none of the Tinc netmasks overlap! Note how the
-192.168.0/16 network covers the entire address space of the three hosts.
-We will refer to the 192.168.0/16 network as the `umbrella' from now on.
-As you can see we can fit 256 hosts into this umbrella this way, which is
-also the practical maximum for tinc. Let's name our VPN 'fubar'.
-\f
-The configuration file
-----------------------
-Let's create a configuration file for f00f. We have to put it in
-/etc/tinc/fubar because that's how we named our VPN.
-
- MyOwnVPNIP = 192.168.1.1/24
- VpnMask = 255.255.0.0
- ConnectTo = 126.202.37.81
- ConnectTo = 103.22.1.218
- TapDevice = /dev/tap0
-
-The first two lines tell Tinc about the numbers we have chosen above.
-Using the ConnectTo lines, the daemon will seek contact with the rest of
-the umbrella. It's possible to configure any number of ConnectTo lines,
-you can even omit them so that it just sits and waits until someone else
-contacts it. Until someone does, the poor daemon won't be able to send
-any data because it doesn't know where everybody is.
-The TapDevice is where the tinc daemon will interface with the kernel.
-\f
-The passphrases
----------------
-We will have to generate keys for ourselves, and get a key from everybody
-we want to ConnectTo. All of these go into a directory named
-/etc/tinc/fubar/passphrases. PROTECT THIS DIRECTORY!
-
- mkdir -m 700 /etc/tinc/fubar/passphrases
-
-To generate our own key:
-
- genauth 1024 >/etc/tinc/fubar/passphrases/local
-
-You should then proceed to give this key to anyone who wants to ConnectTo
-you. DO THIS IN A SECURE MANNER! Anyone who has this number can do icky
-things to the umbrella network! Encrypt it using PGP, GPG or another
-program using asymmetric keys. Read it over the phone (without anyone
-listening of course). Send it by snailmail. Write the key down and bring
-it to your partners personally!
-
-If you get any keys from your partners, store them under their network
-number. For example, the key we get from fdiv's network administrator
-will be stored in /etc/tinc/fubar/passphrases/192.168.2.0 (note the 0).
-\f
-Running the daemon
-------------------
-If you use a package manager to install Tinc, the startup scripts use a file
-called /etc/tinc/nets.boot to see which umbrella's exist. It has a line
-per VPN, and lines starting with a # are ignored. Ours will contain:
-
- # Example VPN from the HOWTO
- fubar
-
-In Debian, /etc/init.d/tinc start will start the daemons.
-
-If you use Doohickey Linux just like we do, you'll have to edit the systems
-startup scripts by hand. It should contain something along the lines of:
-
- insmod ethertap -s --name=tap0 unit=0
- ifconfig tap0 hw ether fe:fd:c0:a8:01:01
- ifconfig tap0 192.168.1.1 netmask 255.255.0.0 broadcast 192.168.255.255 -arp
-
-There are two things to note here! First, the MAC address of the ethertap
-device is very important. It must start with fe:fd, and end in the
-hexadecimal representation of the VPN IP number.
-Second, the netmask of the tap device is set to that of the umbrella!
-
---
-$Id: HOWTO,v 1.6 2002/04/12 08:25:01 guus Exp $
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