In the directory which hosts the NCSA package, you will find a file called config.tel. Edit it with your favorite editor and add the following lines:

name=default host=yourlinuxhostname
   hostip=192.168.0.1 gateway=1

Of course, write the name of your Linux box instead of yourlinuxhostname and change the gateway address given here (192.168.0.1), which is only an example.

Now save the file, try to telnet your Linux box, then a machine somewhere out there...