From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.10) Gecko/20050720 Fedora/1.0.6-1.1.fc4 Firefox/1.0.6 Description of problem: Suppose you are ssh-ing from an primary (FC4) host to some other FC4 machine. Before doing this, you make an "xhost + <this other machine>". In the remote ssh session, you set the DISPLAY var to "<your primary host>:0". But now, if you are starting an X application on the remote FC4 machine, this appl is not able to make graphical output to the primary machine: Error: Can't open display:. Even when using "ssh -X" for openeing a session to the remote machine an changing there the DISPLAY variable to <primary host>:0, graphical output to the primary host fails. But a pure "ssh -X" to the remote host allows grraphical output with no trouble. Version-Release number of selected component (if applicable): openssh-4.1p1-3.1 How reproducible: Always Steps to Reproduce: 1.xhost +<remote host> 2.ssh <remote host> 3.remote_host#: export DISPLAY=<primary host>:0 4.remote_host#: start some graphical app on <remote host> 5. Error: Can't open display: ... Actual Results: see above Expected Results: see above Additional info: --
The X server listens only on UNIX sockets, not on IP. Using raw X over network is a security nightmare. ssh -X works because it redirects X communication through its encrypted connection.
It seems this is a new effect of the X server. In earlier FedoraCore or RedHat versions, working in this manner was possible (X is a network protocol, and security is _my_ problem in this connection), so I am not satified with your answer.!