It can be pretty useful to know the version of your X server installation.
There are at least two ways to get this piece of information. As root, issue one of the following commands :
root@localhost:~# xdpyinfo | head
The last command will display the first 20 lines from the output of xdpyinfo
Make sure you have the package x11-utils installed so that the command xdpyinfo will be available.