Remote X Windows on Fedora vs. Redhat9?

[Thomas]

I found the remote X Window thingie does not work anymore like it did on 
Redhat 9.
I used to simply log into a remote host, issue an export 
DISPLAY=hostname:0 and eventually a xhost + command on the local 
machine, so that i could use GUI Apps from the remote host displayed on 
my local X server.

Running fedora, i simply get the message
Error: Can't open display: nova:0

(no firewall on the local fedora machine, also 'xhost +', so all 
displays should be allowed. )

Any idea why it does not work like on Redhat 9 anymore?

thanx

Thomas