A Class on the Net for Librarians with Little or No Net Experience

LESSON 17: TELNET, PART 1: THE UPSIDE

"If you look like your passport photo, in all probability you need the journey."

-- Earl Wilson, 1961


Telnet could be described as "virtual reality," because it really is a form of "being there;" telnet allows you to connect to remote computers and run applications on them as if you were working from a workstation directly connected to the remote host.

The Telnet function and command (in Net lexicon, it serves as both adjective and verb) is appropriate for reference and research purposes because, through telnet, you can access and search public information resources around the globe; this includes huge databases and practically every major library catalog worldwide.

Library catalogs constitute the most frequently visited telnet sites, with over 1,000 OPACS currently accessible via the Internet. Telnet also allows you to connect to fee-based, online information services and to participate in interactive multi-user games. Through telnet, you can gain entry to the private accounts you maintain on your own or remote computer systems and access them from home or away. Many conference centers now set up kiosks running telnet so you can connect to your host computer back home, edit files, run applications, or just check your email!

Telnet allows you to connect directly to a remote computer without going through, say, a gopher menu. Within telnet, you type commands on your computer which are then carried out on the remote computer almost instantaneously. It's as if your computer were actually connected via a LAN (local area network) to that remote computer host. You become, in effect, just another terminal on the host computer's system, running applications, browsing, maybe editing files and, in general, working as if you were directly connected to the host.

HOSTNAME AND IP ADDRESS

When telnetting to another computer, you will need specific login instructions for the site. Most importantly, you will need the hostname of the system where you wish to connect. This can be either an alphabetic name or an IP (Internet protocol) number. The IP address assigned to Internet hosts is always composed of four sets of numbers. Because these numeric addresses are tough to remember, most hosts have registered alphabetic names for others to use when making connections.

Let's use the University of South Carolina as an example. The CMS mainframe at USC, which supports email and file functions, has both an alphabetic name and an IP number:


    alphabetic name:  vm.sc.edu

    IP number:        129.252.41.4

When I want to check my email or access my files from a remote site, I telnet into the CMS mainframe at USC using a 3270 version of telnet and the CMS alphabetic name or IP number.

The MVS mainframe at USC, which serves up public access to the USC electronic library catalogs of our multi-campus libraries, also has both an alphabetic name and an IP number:


    alphabetic name:  mvs.sc.edu

    IP number:        129.252.44.2

When I wish to connect to a USC Library catalog from a remote site, I must telnet into the MVS mainframe at USC using a 3270 version of telnet and the MVS alphabetic name or IP number.

Take care when noting hostnames (they must be exact!), and if given both the alphabetic and numeric versions in system access instructions, make a note of both: there may be instances when system problems will prevent you from connecting with the alphabetic version, but the numeric will work in this pinch.

NOTE: while you can use the numeric and alphabetic names interchangebly for most internet connections, don't try to use the IP address for email -- it won't work from many systems.

PORT NUMBER

Many telnet addresses carry a port number at the end of the string. The port number is a specific terminal or server location -- a particular "port of entry" to the information being sought. You can usually safely open an address without specifying a port number in telnet (and gopher) connections. However, if you are given instructions with a port number included, it's a safe bet that it's needed to make the connection. Stay on the safe side and, whenever you see a port number listed, use it.

MAKING THE INITIAL CONNECTION

When you telnet to a remote host, (in addition to supplying the hostname and optional port number) you will usually be asked to respond with a specific login id. Sometimes, in order to reach the appropriate system, you will be asked to select specific options from a menu. These special procedures have been put in place by the host site to ensure that you'll only reach those files and applications available to guest users.

If you are telnetting to a public telnet site that requires a special login, or prompts you for other information, you should receive the instructions you need either on-screen or in a published guide.

Here are some typical telnet sites, with their hostnames and login instructions:

Note to Webbers: If you are attempting to make these telnet connections from a web browser, please note that while telnet connections are supported, you usually must also have a telnet application installed on your workstation, and you must configure your web browser to make it work; look under "options" or "preferences" in your browser for an applications setup menu where you can direct your browser to an actual telnet application on your harddrive (ask your sysadmin for a little help on this one if you need it!).

Even after you have successfully made the initial connection, remember that procedures for use of each database and library catalog on the Net are potentially very different from others you may have used. Always look for offers of online HELP and read them before you proceed. In some instances you may be provided with phone numbers and possibly email addresses from which to request assistance or written system documentation. It's not a bad idea to take advantage of all such offers.

It is also important to note that many telnet-based databases, like gopher-based services, have been or are being rewritten as web-based applications. Always look for current dates when visiting a site and pointers to web-based versions of the database (which may be more up-to-date).


YOUR ASSIGNMENT:

If your Internet connection provides you with telnet capability, familiarize yourself with the telnet function by telnetting to the following site:

ELECTRONIC WEB RESOURCES

Or, avoid the perils of "direct" telnet, (sometimes not unlike the "Perils of Pauline"), and --


* "BCK2SKOL" is a free electronic library classroom created by Ellen Chamberlain, Head Librarian, University of South Carolina Beaufort, and Miriam Mitchell, Sr. Systems Analyst, USC Columbia. Additional support is provided by the Division of Libraries & Information Systems, University of South Carolina Columbia.


Your feedback and support for BCK2SKOL are appreciated; please email link updates, suggestions and comments to: eechambe@gwm.sc.edu

Return to BCK2SKOL Index

Go to Next Lesson

Links checked 6 January 1999. See the BCK2SKOL homepage for course update details.
Copyright © 2000, the Board of Trustees of the University of South Carolina.
URL: http://www.sc.edu/bck2skol/fall/lesson17.html