Remote X applications (Re: [Techtalk] Re: Discovering my IP address)

[Mary]

On Mon, Mar 15, 2004, Sue Stones wrote:
> I need to conect to a computer with telnet where I want to use Matlab.
> I have been told I need to "direct the display to an x-windows capable
> computer" I think that means give it my machine's address.  I need to
> give this to Matlab (set the enviroment variable DISPLAY) so that it
> can display a window on my computer.
> 
> What I thought I needed was the IP address used over the internet.
> But even though the above seemed to give me that it still doesn't
> work.

You normally set DISPLAY to "IPADDRESS:0" (where :0 is a screen number)
however, I don't think that will work either.

When you give an IP address as part of DISPLAY, the remote machine will
attempt to connect to the machine with that IP address on port 6000 (I
believe). However, it sounds like it's your firewall/router that
actually has the address and your machine is sitting behind it. If your
own machine doesn't have a publicly accessible IP address, there's no
way that the remote server can connect to it to launch a local window.

What I normally do in this situation is:

local$ ssh -X remote [connect to remote, forward X over the open ssh connection]
remote$ application &

Provided that the ssh session you have will let you forward X over ssh,
this will hopefully bypass your firewall.

-Mary