INSTALLATION INSTRUCTIONS for SECNET

Ensure that you have libgmp2-dev and adns installed (and bison and
flex, and for that matter gcc...).

If you intend to configure secnet to obtain packets from the kernel
through userv-ipif, install and configure userv-ipif. It is part of
userv-utils, available from ftp.chiark.greenend.org.uk in
/users/ian/userv

If you intend to configure secnet to obtain packets from the kernel
using the universal TUN/TAP driver, make sure it's configured in your
kernel (it's under "network device support" in Linux) and that you've
created the appropriate device files; see
linux/Documentation/networking/tuntap.txt

If you're using TUN/TAP on a platform other than Linux, see
http://vtun.sourceforge.net/tun/

Then, to install secnet do

$ ./configure
$ make
# cp secnet /usr/local/sbin/secnet
# mkdir /etc/secnet
# cp example.conf /etc/secnet/secnet.conf
# cd /etc/secnet
# ssh-keygen -f key -N ""

(When upgrading, just install the new /usr/local/sbin/secnet; keep
your current configuration file.)

If you intend to start secnet as root, I suggest you create an userid
for it to run as once it's ready to drop its privileges. Example:
# adduser --system --no-create-home secnet

Generate a site file fragment for your site, and submit it for
inclusion in the vpn-sites file. Download the vpn-sites file.

* Constructing a site file fragment

You need the following information:

1.  a short name for your site, eg. "greenend". This is used to
identify your site in the vpn-sites file.

2.  the name your site will use in the key setup protocol,
eg. "greenend" (these two will usually be similar or the same).

3.  the DNS name of the machine that will be the "front-end" for your
secnet installation. This will typically be the name of the gateway
machine for your network, eg. sinister.dynamic.greenend.org.uk

secnet does not actually have to run on this machine, as long as the
machine can be configured to forward UDP packets to the machine that
is running secnet.

4.  the port number used to contact secnet at your site. This is the
port number on the front-end machine, and does not necessarily have to
match the port number on the machine running secnet.

5.  the list of networks accessible at your site over the VPN.

6.  the public part of the RSA key you generated during installation
(in /etc/secnet/key.pub if you followed the installation
instructions). This file contains three numbers and a comment on one
line. The first number is the key length in bits, and can be
ignored. The second number (typically small) is the encryption key
'e', and the third number (large) is the modulus 'n'.

If you are running secnet on a particularly slow machine, you may like
to specify a larger value for the key setup retry timeout than the
default, to prevent unnecessary retransmissions of key setup
packets. See the notes in the example configuration file for more on
this.

The site file fragment should look something like this:

shortname {
		name "sitename";
		address "your.public.address.org.uk";
		port 5678;
		networks "172.18.45.0/24";
		key rsa-public("35","153279875126380522437827076871354104097683702803616313419670959273217685015951590424876274370401136371563604396779864283483623325238228723798087715987495590765759771552692972297669972616769731553560605291312242789575053620182470998166393580503400960149506261455420521811814445675652857085993458063584337404329");
	};