X and term

term allows users to open up X windows on the local machine from clients that are running on a machine on the network. This is done by using the txconn client. txconn is executed on the remote, network-connected machine, it is invoked simply as txconn. It goes into the background and returns a number on the standard output, this number is the display number that clients should use to access the X server on the local machine. An example should make this clear. I am logged in, via trsh, to my remote term host, named foo. On foo, I do the following

 
foo$ txconn 
Xconn bound to screen 10 
:10 
foo$

Now, on any host that I wish to run an X client, that is to display on my local machine's X server, I do setenv DISPLAY foo:10. Now when I start the client, it will try to connect to screen 10 on machine foo, but txconn is listening to this screen, and will forward all X protocol packets via term to the X server on the local host - i.e. the window will open up on your local machine.

It is possible to go the other way - run a client on your local machine and have it open up a window on a remote machine on the network, however we will defer explaining this until after we have discussed tredir.

txconn is not terribly secure, anyone can connect to your local server via term and perform all sorts of mischief. If you're worried about this sort of thing, it might be a good idea to consider using xauth to authorize your connections. Consult the xauth man page.

The X protocol is not very efficient, it wastes some bandwidth. This is usually not a problem over an ethernet, but can be murder over a modem. X11R6 is supposed to introduce a low bandwidth version of the X protocol, LBX. However, this is not of much use, since R6 has not been released at the time of this writing. There is a utility named sxpc which compresses the X protocol, improving response over serial lines. sxpc includes a writeup on how to get it working with term, and is recommended. You can get sxpc from ftp.x.org in /contrib. The sxpc package also explains how to use xauth, so it is doubly recommended.