Re: Telnet client problems

I've had similar problems in the past but have a different take on it.  I'm
sure someon like Mark B. can correct me but here goes at a 50,000 view.

Telnet has a number of negotiations that occur.  One being term type.  In
prior releases the AS/400 telnet client started with 3179.....life for the
most
part was good.  At some point (I believe v3r6 or r7) the client started
with
3477 FC (DO).  If the telnet server can't support this it should come back
with
a DON'T.  Each side should progress down their list until they reach a
common ground.

Some servers do not negotiate term type but rather have a table that they
use to control term type functions.  Changes in the client request can
cause
problems.  I had this specific problem occur whereas the AS/400 changed
but was doing things 'correctly' and the server was the real culprit.
Therefore,
term type was not being negotiated and the AS/400 thought it was 3477 and
the remote system was operating as a VT110.......

If you want some more info. I highly recommend TCP/IP Illustrated Volume 1
by W. Richard Stevens.  BTW, as of V3R6 I don't believe you can actually
force the AS/400 telnet client to start negotiating at a specific term
type.  In
prior releases you could (v3r1 I believe).




I used to have problems connecting to Linux machines via the AS/400 telnet
client. Every time I tried, the telnet server on the Linux machine would
dump
core and hence immediately close the connection.
On inspection of these coredumps, it turns out the AS/400 telnet client
insists
on a specific terminal type (like IBM-3477-FC, or whatever AS/400 screen
you
happen to try from) which of course is unknown to the Linux Server.

It strikes me as extremely odd that even though I specify *VT100 or *VT220
on
the AS/400 telnet command that it should do this rather than request a
vt100
session.

Anyway, the fix was to create a soft link with the above name pointing to
the
VT100 terminfo database entry. This way a connection can be established.
The problem: if you happen to try to telnet to a server that doesn't have a
link
with your current terminal name your SOL.
To me it appears that unless you are the administrator of the server you
telnet
to, the AS/400 telnet client is a waste of DASD.
Any comments?

Regards,
Matthias

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Matthias Oertli, Sydney, Australia








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