SimpleDynDNS is a simple set of scripts to track dynamic IP addresses. It does
so using SSH-based authentication. Much like e.g. gitosis, the login shell is
replaced with a script that will update a map of IP addresses.

Project home: http://github/patrikf/simpledyndns

Setting up the server
=====================

Create a user:
	# adduser --disabled-password simpledyndns

Create the authorized_keys file and set the permissions correctly:
	# cd /home/simpledyndns
	# mkdir .ssh
	# touch .ssh/authorized_keys
	# chown -R simpledyndns .ssh
	# chmod -R go-rwx .ssh

Copy the scripts in server/ to /home/simpledyndns/.

Adding a client to the system
=============================

Introducing a new client to the server
--------------------------------------

Generate a SSH keypair on the client. I just use /etc/ssh/ssh_host_rsa_key.

On the client, get the public key:
	$ cat /etc/ssh/ssh_host_rsa_key.pub
	ssh-rsa _BASE64ENCODEDPUBLICKEY..._ _COMMENT_

On the server, add the public key to /home/simpledyndns/.ssh/authorized_keys by
adding a line like this:
	[TODO] _BASE64ENCODEDPUBLICKEY..._ _COMMENT_

Setting up the client
---------------------

Copy the script in client/ to /etc/network/if-up.d/.

Adjust the variables in the script to match your setup.

If your IP address can change while the network stays up, you will have to find
some other way of running the scripts whenever this happens. A simple solution
might be using a cron job.