From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20041215 Firefox/1.0 Red Hat/1.0-12.EL4 Description of problem: Xapps on remote systems fail to run on the local machine: [root@rhodan ~]# xhost + access control disabled, clients can connect from any host [root@rhodan ~]# set|grep DIS DISPLAY=:0.0 [root@rhodan ~]# export DISPLAY=rhodan:0.0 [root@rhodan ~]# xclock Error: Can't open display: rhodan:0.0 I can no longer run an x application on a remote system and display it on the local machine. THIS USED WORK WITH EARLIER RED HAT OS. Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1.xhost + 2.export DISPLAY=local machine name (e.g. rohdan) 3.xclock Actual Results: Error: Can't open display: rhodan:0.0 Expected Results: xclock should have been loaded and running Additional info: I see this only with Red Hat Enterprise Linux AS release 4 (Nahant)
X11 over TCP is disabled by default in all Red Hat operating system releases since about Red Hat Linux 7.0 and must be manually re-enabled by the administrator or user prior to remote X11 applications working over direct TCP. Red Hat strongly recommends using ssh with X11 forwarding instead of enabling communication with the X server over TCP, as ssh traffic is far more secure. By default however, X11 forwarding is disabled in openssh in RHEL4, so must be manually enabled. If you have an appropriate support contract with Red Hat, please contact Red Hat global support services at http://www.redhat.com/apps/support or via telephone at 1-888-RED-HAT1 if you require assistance reconfiguring your system to use ssh with X11 forwarding, or to enable the X server to listen to TCP connections. Hope this helps.