I'm running RedHat Workstation Version 4 for iA64. When I telnet (ssh is unavailable) to another server then export DISPLAY=hostnam:0 and attempt to launch a motif application (or xclock for that matter) I get Error: Can't open display:

I tried xhost + to no avail.
My firewall is disabled
Is there some other security settings I need to turn off?

A normal X11 session would be (assuming bash as shell):

peter@mycomp> xhost +yourcomp
peter@mycomp> telnet yourcomp
peter@yourcomp> export DISPLAY=mycomp:0.0
peter@yourcomp> someapplication

If you are using csh (or tcsh), the cmd line would be
peter@yourcomp> setenv DISPLAY mycomp:0.0

If it is not this and you did it in this order(or close), it may be a NAT issue. Are you or the computer you are accessing NAT'd? If so, you may have to forward the X11 port the the NAT ip. SSH has X11 tunneling.

Not a NAT issue, make sure the firewall is off on the host server. Try to nmap it to see if you see the X11 port (6000).


Pete

Not a NAT issue, did the xhost thing in that order. Ran through the security settings to disable the fire wall. Did a netstat -a and could not firn X11 on port 6000. But found...

[root@tdjhhp2 ~]# netstat -a | grep X11
unix 2 [ ACC ] STREAM LISTENING 6429 /tmp/.X11-unix/X0
unix 2 [ ACC ] STREAM LISTENING 7727 /tmp/.X11-unix/X1

Is there some other security setting I need to remove?

Thanks

Sorry for the late response.

If you use netstat -a, it resolves port 6000 as x11.

do a netstat -a | grep x11

my results are:

tcp 0 0 *:x11 *:* LISTEN
tcp 0 0 *:x11 *:* LISTEN

if you do a netstat -a --numeric-ports | grep 6000

you should get:

tcp 0 0 *:6000 *:* LISTEN
tcp 0 0 *:6000 *:* LISTEN




Another test would be on the machine you are telneting to. Log directly on the console of the remote machine. If you echo $DISPLAY, then you should see :0.0 returned. Then try setting display on this shell, ex.

my@mymachine> export DISPLAY=mymachine:0.0

Then try opening an app, like xclock. If still doesn't work, try:

me@mymachine> xhost +
me@mymachine> telnet mymachine
login: me
password: *******
Last login: Tue May 23 18:51:45 on :0
me@mymachine> export DISPLAY=mymachine:0.0
me@mymachine> xclock

FYI, you can set display also on the command line:

me@mymachine> xclock -display mymachine:0.0

Very curious as to what it could be.

Question: Is it just motif apps, or all apps?

Pete

Apparently by defalt in the gdm.conf file there is a statement DisallowTCP=true that needs to be set to false or commented out to allow this to work. I set it to false and all is fine now