[ale] Linux Telnet vs NT Telnet

[Jacob Langseth]

Patrick Ramsey [SMTP:Ramsey_Patrick at promina.org] wrote:
> Problem: I can not telnet from my linux box or my 95 workstation into a
> synoptics lattisnet terminal server.  I can ping it fine so I know that its
> not a gateway / subnet issue.
>
>     Anyway, I was forced to use my compadre's NT box and low and behold it
>     came up fine.  (He doesn't know I stooped to NT yet and I am attempting 
to
>     keep it under wraps)  But configuring serial devices is part of my job 
and
>     if Linux's Telnet is flawed I will have to go with something else.
>      (Whatever the problem is with Linux it also is in 95)
>
> I can't imagine it would be the emulation.  All three boxes are set to
> vt100.
>
> Any clues?  Anybody run into this before?

Likely this stems from differences in telnet option negotiation handling.
One thing you can try from the linux box is see if
	nc -vv -t <host> 23
is successful.  Nc is hobbit's netcat utility, -t tells it to perform telnet
option negotiations.  Rather than answer the questions legitimately,
netcat answers no no no no no no to every option the host wishes to
set, and as such should allow access from the linux server.

If you want to get nitty gritty with the session, grab a
	tcpdump -vv -s 256 -x -l -S '(host <dest> and (port telnet))'
dump of the session from an NT source, and then another dump
from the linux source, go through the hex codes and see where
the option negotiation is failing.  I've found the telnet.h file included
with the ztelnet implementation to be a useful reference, as well as
a couple of rfc's which I had printed but seemed to have misplaced...
searching for 'telnet option' on your favorite rfc repository could
prove useful should you choose to pursue it.

Hope this helps,
Jacob

--	     	   	   	       		    	  		
Jacob Langseth  	
Vodavi-CT, Inc.		<jlangseth at vodavi-ct.com>