X11 tunneling windows

PuTTY should be preconfigured to work in conjunction with Xming. All connections are initiated through PuTTy. Xming will simply provide an X-server in much the same manner as a standard Unix workstation. PuTTy will forward your X information from each host when you establish a connection. Using this configuration, an X-Windows window will automatically open whenever you start an X-Windows program on the remote Unix host.

A good X-Windows program to test with when you first set up Xming is xclock. At the command prompt, enter the following and a small window containing a clock will open on your PC's screen. It might open minimized; if you don't see it right away, check your taskbar. Many exist, but in our experience the following have worked well:. To use X11 in an interactive shell, first ssh into the login node from your local machine with the -X or -Y flag:.

After you log in, run glxgears to verify that your X server is functioning properly. If so, you should see a small window that looks something like this, most likely on the upper-left corner of your screen:. If you would like to run a GUI on a compute node, you must first request a job allocation, and then ssh into the node you receive using the -X flag.

Submit a ticket. Your feedback is important to us, help us by logging in to rate this article and provide feedback. You have to remove these settings before you can use it with SSH X11 tunneling. In the above, the adabyron. A good X-Windows program to test with when you first set Exceed up is xclock. It might open minimized; if you don't see it right away, check your taskbar. That's the case, say, for electronic mail. The Eudora or Outlook or Netscape that you use on your personal computer is your email client , and it talks to the POP or IMAP server on the remote machine that your email account is on -- icarus, mailserv, or tigger, for example -- which serves your email.

In normal client server software the security question -- making sure that only you can access your own email, to continue our example -- is taken care of on the server side. You start your client, tell it which remote server to use and what your login id and password for that service is. Then your client contacts the server and gives it your id and password, which the server either accepts or rejects.

Thus, when you use Exceed, the server is on your personal computer -- the local host -- and the clients are on the remote host -- icarus, tigger, or whatever other Unix workstations you have accounts on.

The article is a bit more detailed than I'd like, but it's readable and complete. While this local server vs. The obvious answer to the "which processes should be allowed write output to my personal computer" question is only those client process that you start using your own Unix account s. That is, unfortunately, rather hard to do.

So people often set their X Servers up by defining "trusted hosts" using Xhost security, which is easier but still somewhat hard , and which gives any account an a specific Unix host permission to open up an X-Windows window on your personal computer.

If that doesn't scare you, think again. It ought to. Thus, if you tell Exceed that tigger is a trusted host, as described in Using Exceed X Server with Xhost Security , then anyone logged into tigger will be able to open an X-Windows window on your personal computer, read all the windows managed by your X Server, including those where you typed passwords, regardless of whether you can read the password on your screen, or change the X Server settings that are read by other clients.

This really should scare you. And as insecure as Xhost "security" is, even that level of security is reasonably hard to set up, because your local machine has to know about each remote host you're going to be using X Windows with, and because each remote host has to know which personal computer your X Server is on.

The latter makes it hard to use X Windows from different machines -- say the one in your office or dorm room and one in a public lab -- you have to change settings on your Unix account each time you change local machines. SSH with X11 tunneling, on the other hand, is both easy to set up and secure, because it puts the client software back on your personal computer. You can use it on any personal computer to run X Windows from any remote Unix host that you have an account on and that supports SSH X11 tunneling, without changing any settings on the X Server or on the remote host.