It is a long standing practice on a Linux desktop system that runs X to disable the TCP listening port which defaults to 6000. This port is by default enabled and a potential security risk, a nasty one since most people never access their X server via network.
On my desktop I run slim as my login manager so all the how-tos and stuff I read simply did not do the trick. I had to resort to some hard core reading. In the end it was more simple than I though. Most methods use the display manager, such as xdm, gdm or kdm to pass the “-nolisten tcp” option to the server which disables it. Since I use none of these I resorted to reading the docs on slim. Turns out slim also supports this via its config file.
The slim config file has a line which is commented out by default for “xserver_arguments”. I un-commented this line and made it read:
xserver_arguments -nolisten tcp
A restart of the X server and port 6000 was closed.