X-server question

[VJ]

Hello,

I have perhaps a strange question. At work, I am working on a Mandriva
Linux system. I would now like to run a linux application from the
university. But there is a problem: the computer at the university
(let's call it B) is not visible from outside. So I first have connect via
a secure shell to the visible server (let's call it A). On A it is not
possible to run applications (but I can launch an xterm and it shows on my
desktop at work. To run the application I need, I then connect via ssh to
the internal machine B (ssh B), but I don't know how to configure my
display variable so that when I start for instance an xterm on B, it also
shows up on my desktop.
Any solutions?


Thanks!


Jörg

[FatBastard]

Did you try ssh with X forwording?
home$ ssh -X user@A
A$ ssh -X user@B
B$ applicationName

[VJ]

I didn't, but tried it and it works...

Thanks!


Jörg

[VJ]

Oh, one more question...

How much traffic is generated when running applications remote? I suspect
it is less then for instance with a remote desktop, as the transmitted
information is more content based rather than just the graphical window
that is transmitted...? Right?


Jörg

[FatBastard]

I am not sure I understand your question ... but in principle, when ever you connect to an X server, all the traffic consists of X protocol data. usually you connect to localhost X server.
when you run a X forwarding ssh session, the same amount of data (X protocol data) is transmitted, it is encrypted though.
If traffic is an issue to you you can try and use -C parameter. this will compress (gzip) ALL the ssh transmitted data (including X11).
IMHO this makes a difference when bandwidth / traffic is an issue.

if by saying Remote Desktop you refer to the MS RDP, or unix's VNC then yes. X generates less traffic.

[VJ]

Thanks, it was a good answer to my unclear question.

I just had a basic knowledge of Linux, X and the like. Just recently
I began to use it more intensly, as we are now using it as a developer
platform for software (cross platform, we have a windows machine for
verification purposes).


Thanks again!


Jörg

[FatBastard]

When it comes to which generates more traffic, I have to add that its very usage dependend. RDP and RFB (vnc) both compress, and send frames by polling for changes. so it might send less data then X11 in some cases.

Happy Linuxing ;-)

[VJ]

When it comes to which generates more traffic, I have to add that its very usage dependend. RDP and RFB (vnc) both compress, and send frames by polling for changes. so might send less in some cases.

Yes... but the windows are drawn remote and then transmitted as images (so to speak). Whereas in X (if I understand properly), the window contents are transmitted, and the window is drawn on the server. So if the majority of window contents is textbased (which is the case for me), I guess X is the better option.

I just started with the -C option, and the X-applications work much more fluently.

Happy Linuxing ;-)

Thanks!
(before, I only used Knoppix at home to make images of my windows drives using partimage)


Jörg

[FatBastard]

Here is a solution tailor made for you (not that what you use now is wrong),
at the very least its some interesting reading about the performance question.
this is a fast solution, but I guess you need to be (a little) more advanced, before trying it
x11vnc