I try to set up a distributed X computing environment on a network envolving 3 hosts and need some advice from some X gurus: Configuration: -------------- hostA runs my local X server (X display where I sit working) hostB runs my remote Window Manager (GDM login&session host) hostC runs my remote X client application (execution host) HostA is set up to boot directly into X mode querying and presenting the login screen from hostB (like a X terminal without local login first). HostB and HostC have both individual home directories and passwd for the same users, and both use /etc/hosts and /etc/hosts.equiv. Command dialog: --------------- On hostA I log in to hostB and enter the following commands: hostB-> xhost hostC hostB-> rlogin hostC hostC % setenv DISPLAY hostA:0 hostC % XclientApp The following typical error messages are displayed and theXclientApp doesn't start up or is not displayed on hostA: Xlib: connection to hostA:0 refused by the server Xlib: Invalid MIT-MAGIC-COOKIE-1 key A rlogin to hostA also confirmed that: X: client is rejected from IP_of_hostA Problem: -------- I think the problem is the user access authorisation, that is how to tell the X server on hostA to allow connections also from hostC (X apps) in addition to the connected Windows Manager from hostB. Therefore I also tried first: hostB-> rlogin hostA hostA % xhost hostC which only resulted in the following error message: unable to open display "" Now I need advice from some X gurus? Terje J. Hanssen