The situation looks like this:
There are two comuters COMP1 which is my computer at home and COMP2 to which I have no physicall access - I can only log there thru ssh or gdm. Now I want to log into COMP2 from COMP1, run a program which uses X-Windows and then log out but leave the program running. I guess I have to somehow set a permanent X-Server in gdm so I can log to the same X session but gdm makes a separate X session for each login. Anyway it doesn't have to be using gdm at all - I just need to know how this is solved.