Usage of a telnet client instead of ssh or rsh

Jamie Lokier jamie at
Sat May 13 19:53:10 GMT 2006

Jan-Benedict Glaw wrote:
> On Sat, 2006-05-13 20:27:03 +0200, Paul Slootman <paul at> wrote:
> > On Fri 12 May 2006, Matt McCutchen wrote:
> > > Wayne beat me to it.  But I was going to say, you might be able to write
> > > a wrapper script that sends the rsync command and arguments down the
> > > telnet connection for the shell to execute and discards any extra output
> > > produced by the shell while logging in (to avoid the mystifying "is your
> > > shell clean?" message).  For instance, if you know the shell on the
> > 
> > Don't forget also that there is actually such a thing as a telnet
> > protocol, so a telnet session probably won't give you a real clean
> > connection, some combination of special bytes may trigger telnet to do
> > unexpected things instead of passing the data on transparently.
> > 
> > Is there no way of using rsh in your kerberos-ized situation?
> Well, ignoring the protocol-specific extensions, I'd think of some
> kind of expect(1) wrapped telnet client to do the login and
> command-sending stuff...
> Though that's all a crude workaround. Why don't you just use ssh,
> which is nicely (via GSSAPI) kerberized?

ssh isn't always an option.  E.g. to reach HP's testdrive machines,
telnet is the only available option.

I've done rsync over telnet, in binary mode and with the terminal set
to raw, using Perl and the Perl Net::Telnet module, and it mostly
worked but there were sometimes errors.

-- Jamie

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