8. X Networking and Security

As mentioned, X is essentially a networking protocol with graphical displaying capabilities. This makes for some interesting usage possibilities. And also means there are inherent security considerations, as there is with any networking environment. And if you ever connect to the Internet, you are in the midst of one very large, hostile network ;-)

X clients connect to X servers via various networking protocols, including TCP/IP. Even with just local connections. Possible usages here are to run an application on one computer, and display it on another. Or, to actually log in to a remote system, and have it display to your local screen, with the client apps using the remote system's CPU and RAM.

Without any precautions, this can leave you wide open to various types of mischief and abuse. For instance, anyone logged into to your system can access your "display", meaning they can see what you are doing if they want to. Thankfully, most recent Linux releases come with some default security precautions enabled. But it is best to make sure for yourself that you are protected.

Both X networking and security are nicely covered in The Remote X Apps Mini HOWTO , so we shall not need to try to rehash it here. Recommended reading. See other references in the Links section of the Appendix below.

A few recommended precautions: