NIU Department of Mathematical Sciences
Using telnet

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Telnet is one of the oldest uses of the Internet communications protocols. It allows one computer on the network to access another one as if it were a simple terminal directly connected to the remote machine with a cable.

Telnet follows the standard Internet "client-server" philosophy. The client is the telnet program running on your computer. The telnet server runs on the remote computer that you are connecting to. You use the client to control the remote machine as if you were sitting in front of it and typing commands on its keyboard.

There are telnet client programs for all commonly used computers. Telnet servers, however, are usually not present on microcomputer operating systems. This means that you can use telnet to connect from a Mac to a Cray, but the reverse isn't trivial.

Using telnet clients

If you use a Unix workstation, simply type telnet corn.cso.niu.edu, and you should see a response from that computer. Telnet will terminate when you log out of the remote computer. If the connection somehow gets stuck and the remote computer stops responding, you may have to force telnet to quit. On most Unix systems typing 'Control-[' (Control and left bracket keys together) will take you to telnet's command mode; when you see the prompt telnet> simply type quit and press `Return'.

When the remote computer keeps asking you for the username and password (e.g. you connected to a wrong machine by mistake, or forgot your password), hit `Control-D' at the login: prompt to bail out of telnet.

There are several telnet clients for Apple Macintoshes. The most popular one is NCSA Telnet (which is no longer actively). There is also "Nifty Telnet", and many commercial packages. Double-click on the program's icon. Select "Open connection" from the "File" menu. You should see a dialog box with a field labeled "Host" or "Connect to". Enter the remote computer's address there, and click the "Connect" button. If you connect to a certain host frequently, you can usually create a shortcut for it. In NCSA Telnet, for example, choose "Save Set" while you are connected. From then on you can simply double-click on that settings file to start a session with the same host.

Windows 95 computers come with telnet software included as part of the "Network" program group.

Using rlogin

If you are connecting from a Unix computer to another Unix machine, you can use a variant of telnet which is sometimes more reliable and may avoid certain problems with terminal emulation. Type rlogin corn.cso.niu.edu and press `Return'. The remote computer assumes that the username is the same on both computers, so it only prompts you for the password.

If your account on the remote computer is different, e.g. tf0hst1, you must specify this as follows: rlogin corn.cso.niu.edu -l tf0hst1. You may want to create an alias (shortcut) for this command if you find that you use it often enough.

Last modified: 4/21/97 by webmaster@math.niu.edu