Remote Administration of Linux Systems - page 5
Introducing Remote Adnministration
Remote administration in a graphic console in Linux will always have very high risks and very bad ways of providing security. That's why we need to pay more attention to configuring firewalls and setting tighter user passwords.
On the remote computer, you must close all of the ports from 6000 and higher (the number of ports depends on the running X Window and/or vnc servers) to access from all hostnames except the administrator's. If, for some reason, you must use that access, then use the ssh utility for additional authentification and traffic data encryption.
For vnc we must take additional care about passwords, which can be set up with vncpassword. Never run vnc with root rights.
So, with a little effort installing and configuring some basic tools for remote administration, a system administrator can get some very powerful tools for remote access, which will lighten his load tremendously. Just don't neglect the security side.