Re: What is telnet?

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

From: "Bjorn" <Bjorn@xxxxxxxxxxxxxxxxxxxxxxxxx>

| Can anyone explain telnet??
| --
| Bjorn

Telnet is a protocold that creates a Virual Terminal to a server or Main Frame.

In the old days you would connect a terminal via; RS-232, RS-422, 5250, 337x or other
interface.

With a terminal you have a screen, keyboard and maybe a mouse access into a server or main
frame.
A terminal is dumb. It has no CPU and local processing power. It's only purpose is to
provide a human an interface to a computer.

Prior to TCP/IP if one wanted to access that server or main frame on a PC one would have to
install an emulation card and "hot key" between DOS/Windows and the Terminal Client.

When TCP/IP came about the Telnet protocol was created to perform Virtual Terminal service
of the TCP protocol. The Virtual Terminal service uses the TCP protocol (a sub-set of
TCP/IP) because it is a connection-full protocol. That is you have to logon a create a
connection to the server to access it. Standard Virtual Terminal services use the ANSI or
VT100 set of commands. To connect to an AS400 main frame you would use a TN5250 client
which uses Telnet with a hand-shaking and communcation set designed to communicate like a
5250 emulation card of Yesterday. Instead it uses the 5250 communcation set over TCP/IP.
Similarly you would use a TN3270 client to connect to a IBM 360/370.

Stanard uses of the Telnet protocol (using VT100) are for configuring TCP/IP managed
devices. These could be; Print Servers, Ethernet Switches, Routers and FireWall
appliances.

Examples:

1. I have a HP JetDirect Print Server so I can share one printer with 20 users on a
netlwork (LAN). I can Telnet into the IP address of the Print Server and confgure the
device.

2. I have a Router for my home LAN (SOHO). Depending upon the make and model I can
Telnet into the IP address of the Router and configure that device.

The purpose being to provide a human an interface to that device.

--
Dave
http://www.claymania.com/removal-trojan-adware.html
http://www.ik-cs.com/got-a-virus.htm


.

Relevant Pages

  • Re: step forward using mms protocol with media player
    ... I need to do frame by frame using RTSP protocol, with windows 2003 server EE ... with the latest windws media services. ...
    (microsoft.public.windowsmedia.player)
  • Re: Java sockets and readLine
    ... > Telnet is a predefined protocol. ... I guess my example of a client was flawed, but what I was trying to ... specify was a client using a non-predefined protocol. ... the server and the server locally echo's each line of text while ...
    (comp.lang.java.programmer)
  • Re: The Big Tease
    ... "There is no expectation of privacy on this server." ... It emphasised that there was a specific protocol that was general ... different protocols gould be invented that use telnet. ... Of course there must now be a campaign to correct Nick Wedd's SL page. ...
    (rec.games.go)
  • Re: telnet vs. netcat
    ... When I run the command 'telnet mailhost 25', I can enter SMTP commands ... and elicit responses from the server, ... (or even a protocol family), and 'telnet' is the client program. ...
    (comp.os.linux.security)
  • Re: Stumbling towards implementing telnet
    ... Is it my imagination or is Telnet completely fubar in most instances. ... I used to work with the protocol years ago and seemed like every server ...
    (comp.lang.lisp)