-display localhost:0.0 doesn't work



I try to display x windows programs run on an other computer on my Fedora 10 computer running x windows.

If I press commands like rxvt -display localhost:0.0 I get the answer rxvt: can't open display localhost:0.0

xhost localhost

doesn't help

I have the same problem when I use remote host names and try remote x window programs.
.