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Using Windows telnet

This post is about Windows 95 telnet. The "IAC" means "interpret as command"; "DM" is "Data Mark". Learn more about the telnet protocol here.

More recent versions of Windows make telnet something you have to enable before you can use it. To fix that:

• Open Control Panel -> Programs.
• Click "Turn windows features on or off" . On the list that appears, check the box "Telnet Client".
• Click OK. You now have "telnet"

See Networking troubleshooting for things you might do with telnet in troubleshooting. The Termcap and Terminfo intro can be helpful in understanding emulation problems.

Bare Windows telnet is usually insufficient for real work, which is why most peope use emulators.

Telnet is unencrypted, which makes sniffing passwords possible. Ssh has replaced telnet generally and many Linux distros no longer install the telnetd server.

From: Rob Hamilton <robz@my-dejanews.com>
Newsgroups: comp.unix.sco.misc
Subject: Re: ^C during telnet from Win95 broken
Date: Fri, 05 Mar 1999 17:21:44 GMT
Message-ID: <7bp3qs$vrr$1@nnrp1.dejanews.com> 
References: <36d6e178.1816230581@news>
<36D885D6.5E74111F@dca.net>
<36DFACB5.A7B08A54@zutritt.at> 
X-Article-Creation-Date: Fri Mar 05 17:21:44 1999 GMT
X-Http-User-Agent: Mozilla/4.0 (compatible; MSIE 4.01; Windows 95; DIL0001004)
X-Http-Proxy: 1.0 x6.dejanews.com:80 (Squid/1.1.22) for client 194.42.250.68

Hi,
The windows telnet app is maybe not the best thing to use.
I dont use it myself, but I had a quick look... and funny things are
happening.

It's not a terminal emulation thing, but a telnet protocol
compatibility thing.

Now, instead of the prompt returing after hitting break or ctrl-c (whatever
your interrupt character is) you may see a single "funny looking"
character instead?
This turns out to be 242 (telnetd DM code)
which is usually sent by SCO 5.4 telnetd
in the sequence 255/242 (IAC-DM) on a keyboard interrupt.
My guess was that windows telnet wasnt processing this as expected.
So I tried running "script t" on SCO. This turns off the IAC-DM send
Guess what... windows telnet now behaved properly.
(btw that *isnt* a fix! script will create a huge log file you
probably dont want!)
Also telneting to an old box (SCO 3.2 which doesnt send IAC.DM)
was ok too.

er... At this I gave up. Getting another telnet for windows is probably
the simplest thing to do. (its pretty slow and awful anyway).
If you absolutely must use it you could try replacing the SCO telnetd with
an older version which might be compatible, but I wouldnt recommend that.

regards,
Rob

In article <36DFACB5.A7B08A54@zutritt.at>,
  Nikolaus Volejnik <holzinger.zeit@zutritt.at> wrote:
> I think that this is a problem of all windows machines (NT, 98, 95) because
> the
> the windows-telnet isn�t as well as teerminal emulations like TUN Emul. We
> are using
> TUN Emul for years and never had any problems with escape-sequences like ^C
> or
> others. Maybe this will help.
>
> nik
>
> lenlutz wrote:
>
> > Thats sometime DELETE
> >
> > Michael Ryan wrote:
> > >
> > > Hi people,
> > >
> > > When I telnet to a SCO OSR504 system from Win95 and hit ^C for
> > > the interrupt key, it doesn't work correctly.  I need to send another
> > > character before processing of the ^C occurs.  My stty settings
> > > are fine.  Any ideas?  Any fixes?  TIA.
> > >
> > > Mike
> > > <mike@NetworX.ie>
> > > ---
> >
> > --
> > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> > Most of what I have learned has been taught to me by others.
> > I guess that means I have to teach others what I have learned
> > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
>

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