使用putty + ssh 登陆 X11

Use of X11 on Windows Machines

NOTE: The tools supported at the lab to provide X-11 on Windows systems have changed. Due to security and maintenance concerns, PC-XWare is no longer supported. Users are asked to remove PC-XWare from their systems and switch to Hummingbird eXceed.

Overview

Since Windows does not support X11 based windowing natively, it is necessary to run a special program called an "X Server" that allows your Windows Workstation to do so. The Lab currently supports a product called Hummingbird Exceed for this purpose. Since X-windows does not provide secure connections itself, it is necessary to use it in conjunction with a separate tool that provides this security. This product (PuTTY) must be installed on your PC and configured correctly to provide secure X-Windows connections.

PuTTY is the same tool used to provide all interactive login from Windows to Unix systems at the Lab. Thus, it should already be available on your system. PuTTY and eXceed are designed to work together so that X applications you launch from within the PuTTY login windows will use the encrypted channel created by PuTTY to secure the network traffic used by the x server against sniffing. Note that it is possible to use X-windows without a secure product like PuTTY, though this is no longer allowed at the lab due to security concerns.

Before Installing Exceed

If you have our old (no longer supported) X11 package (PCXware by NCD) installed on your system, it must be (using the Add/Remove Programs applet in your system's control panel) prior to installing eXceed.

If you have already installed eXceed, but the installed version is older than that shown in the "Supported Windows Applications" table on our web page, you need to the existing version prior to installing the current version.

Installing The Current Version of eXceed

EXceed can be installed by users through the usual Add/Remove programs dialog in your Windows system's Control Panel. A series of screen shots are available that illustrate this process for .

Configuring PuTTY to Secure X-Windows

PuTTY should be preconfigured to work in conjunction with eXceed. The only configuration item, is the flag that tells PuTTY to forward X connections. This is set in the PuTTY config panel under connection -> ssh -> tunnels. "Enable X11 Forwarding" should be checked, and the X Display Location box should be set to "localhost:0".

Starting an X Windows session with SSH X11 Tunneling

All connections are initiated through puTTy. Exceed 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.

1. Start the X Server on your PC -- Exceed, that is -- either each time you reboot your PC or whenever you want to use X Windows:
   1. Click the Start button
   2. select Programs -> Hummingbird 10 Connectivity -> Exceed -> Exceed
2. An Exceed button will appear on your taskbar; the icon looks like the letter X with a top hat and cane on it.
3. Start a puTTy session with SSH tunneling enabled and login to your UNIX account.
   1. Click the Start button
   2. Then select Programs->Putty->putty.exe
   3. Select an X11 enabled session and click "Load"
   4. Login

Using this configuration, an X-Windows window will automatically open whenever you start an X-Windows program on the remote UNIX host.

Testing Your Configuration

A good X-Windows program to test with when you first set Exceed up 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.

		neo@jlabs1>xclock &

Troubleshooting

I get the following display errors:

	"Error: Can't open display:"
	"Error: Couldn't find per display information"

This usually means that your X server is not running or you have not enabled X11 forwarding for your puTTy configuration. Please start Exceed and verify your puTTy configuration is as outlined above.