Download Red Hat LINUX VIRTUAL SERVER 4.6 - ADMINISTRATION Installation manual

This command failed, because XliveCD requires an explicit command to allow remote hosts
to connect to it. When the command xhost + (plus means to add authorized hosts) is run,
xclock can finally display on Windows, as shown in Figure 13-2. Remember the program
itself runs on a remote Linux.
Run the following command again. You should get a positive output this time.
gpok224:~ # xclock &
[1] 21915
Figure 13-2 Manual setting of DISPLAY variable
The xhost + command allows any host to access the X Window System server. From a
security point of view, this may not be a good idea. Even allowing just specific hosts is not
enough, because the X Window System 11 protocol itself is not secure. Using SSH tunneling
removes this security exposure. SSH tunneling also prevents firewalls and NAT from
breaking X Window System 11 communications.
It is possible to use an external SSH client that allows X Window System 11 forwarding, or
SSH client embedded in XliveCD itself.
Chapter 13. Miscellaneous tasks
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