TELNET
PURPOSE OF THIS REPORT
Before gophers, hypertext, and sophisticated web browsers, telnet was the primary means
by which computer users connected their machines with other computers around the world.
Telnet is a plain ASCII terminal emulation protocol that is still used to access a
variety of information sources, most notably libraries and local BBS's. This report will
trace the history and usage of this still popular and widely used protocol and explain
where and how it still manages to fit in today.
HISTORY AND FUTURE OF TELNET
"Telnet" is the accepted name of the Internet protocol and the command name on UNIX
systems for a type of terminal emulation program which allows users to log into remote
computer networks, whether the network being targeted for login is physically in the
next room or halfway around the globe. A common program feature is the ability to
emulate several diverse types of terminals--ANSI, TTY, vt52, and more. In the early days
of networking some ten to fifteen years ago, the "internet" more or less consisted of
telnet, FTP (file transfer protocol), crude email programs, and news reading. Telnet
made library catalogs, online services, bulletin boards, databases and other network
services available to casual computer users, although not with the friendly graphic user
interfaces one sees today.
Each of the early internet functions could be invoked from the UNIX prompt, however,
each of them used a different client program with its own unique problems. Internet
software has since greatly matured, with modern web browsers (i.e. Netscape and Internet
Explorer) easily handling the WWW protocol (http) along with the protocols for FTP,
gopher, news, and email. Only the telnet protocol to this day requires the use of an
external program.
Due to problems with printing and saving and the primitive look and feel of telnet
connections, a movement is underway to transform information resources from
telnet-accessible sites to full fledged web sites. However, it is estimated that it will
still take several years before quality web interfaces exist for all of the resources now
currently available only via telnet. Therefore, knowing the underlying command
structure of terminal emulation programs like telnet is likely to remain necessary for
the networking professional for some time to come.
ADVANTAGES AND DISADVANTAGES OF TELNET
The chief advantage to the telnet protocol today lies in the fact that many services and
most library catalogs on the Internet remain accessible today only via the telnet
connection. Since telnet is a terminal application, many see it as a mere holdover from
the days of mainframe computers and minicomputers. With the recent interest in $500
Internet terminals may foretell a resurgence in this business. Disadvantages include the
aforementioned problems that telnet tends to have printing and saving files, and its
primitive look and feel when compared to more modern web browsers.
OTHER APPROACHES
The functionality of the telnet protocol may be compared with the UNIX "rlogin" command,
an older remote command that still has some utility today. Rlogin is a protocol invoked
by users with accounts on two different UNIX machines, allowing connections for certain
specified users without a password. This requires setting up a ".rhosts" or
"/etc/hosts.equiv" file and may involve some security risks, so caution is advised.
Using telnet instead of the rlogin command will accomplish the same results, but the use
of the rlogin command will have the effect of saving keystrokes, particularly if it is
used in conjunction with an alias.
CONCLUSION
Some argue that the future of the Internet lies in sophisticated web browsers like
Netscape and Internet Explorer, or tools such as Gopher that "save" end users from having
to deal with the command line prompt and the peculiar details of commands like Telnet.
While that may be the case, the tendency remains in place for programmers to develop new
software by building on the old. Therefore, knowing the underlying command structure of
older protocols like telnet and rlogin are likely to remain essential skills for the
networking professional in the forseeable future.
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