Install OpenSSH Server
From this point forward, I'd recommend you have a ssh server running. It will save a lot of typing during setup and help with debugging problems later.
Re-insert the server install CD into the drive and:
$ sudo apt-get install openssh-server
Once it is installed and running, discover the ip address of this machine on your network, so you can log in remotely, if needed:
$ ip addr
user@mythbackend:~$ ip addr 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:1a:92:1c:be:20 brd ff:ff:ff:ff:ff:ff inet 192.168.1.103/24 scope global eth0
Now you can log in remotely in a forwarded X session by replacing your user and address in the following command from the remote computer:
$ ssh -Y firstname.lastname@example.org
You can remove the server install CD at this time.