SSH Display Problem

[Bevan C. Bennett]

Mike Chepesky wrote:
> I have a problem relating to SSH and how it handles the creation of new 
> xterm windows. I have an account at my school, and I can log in via SSH 
> using "ssh -l login_name server_name". When in the labs on campus, there 
> is an X Windows environment, and when certain programs are run (e.g. 
> Matlab, emacs), another xterm window will be created.

Why would running emacs or matlab create a new xterm? Wouldn't they 
create a new emacs or matlab window, respectively?

> However, when I log in remotely using the above command, and run 
> "matlab" or "emacs", the system just seems to hang, not creating a new 
> xterm window. I looked around for a solution, and it seemed that it 
> might be in the /etc/ssh/ssh_config file. However, this is read-only and 
> cannot be modified, nor can the permissions be changed using chmod. Any 
> suggestions?

The first useful debugging tool for potential ssh issues is the "-v" 
switch. Try "ssh -v -l login_name server_name" and watch the exciting 
output.

Make sure you see something like

debug1: Requesting X11 forwarding with authentication spoofing.
debug1: channel 0: request x11-req

Then try running 'xterm' on the remote system and see what output you 
get. I see something like the following:

debug1: client_input_channel_open: ctype x11 rchan 3 win 65536 max 16384
debug1: client_request_x11: request from 127.0.0.1 52686
debug1: fd 7 setting O_NONBLOCK
debug1: channel 1: new [x11]
debug1: confirm x11

It's odd that your application just hangs... usually it will either 
succeed or return an error message.