Re: your mail -- LINUX5250

On Wed, Oct 06, 1999 at 10:02:51AM +1000, Alex Brainman wrote:
> 
> ----- Original Message -----
> From: Jason M. Felice <jasonf@Baldwingroup.COM>
> To: <LINUX5250@midrange.com>
> Sent: Wednesday, 6 October 1999 2:45
> Subject: Re: your mail
> 
> 
> >
> > Hmmm....  You would need some sort of program like netcat (a command
> called
> > 'nc' would be installed) to get a raw connection to the 400, port 23, then
> > you'd have to immediately change the emulation on the terminal, assuming
> the
> > terminal lets you, and assuming the terminal negotiates properly with the
> > AS/400 once it does (not likely).
> >
> 
> I have telnet (running on Windows) that supports primitive vt100 and tn5250
> that would, probably, do the job with 'netcat' you've mentioned - as long as
> it'll pass whole as400 session, including telnet negotiation and the rest,
> as is.
> The program will renegotiate terminal type as many times as necessary.
> If someone can help Berry get this 'netcat' thing setup, I can send my
> telnet
> in to see if it works. I can even twist it around if there are little
> discrepancies.
> 

Hmm, I've thought about it a little more, and there's another sticky reason:
I don't know a way to prevent the telnet daemon on the 'nix box from
telnet-escaping the telnet negotiation the AS/400 would send, or intercepting
and interpreting the telnet negotiation sent by the client on the PC.

Now there's a feature to implement, 'nix telnet passthru ;) you could implement
it very simply by having the instance of telnetd handling your connection
respond to SIGUSR1, for example, to toggle whether it will passthrough or
ignore telnet escape sequences ... nifty ;)  Actually only useful if an
intermediate host can't emulate a terminal type with comparable functionality
as the end host.

A 'pt' utility could open a raw connection, and if the connection is
successfully established, send a SIGUSR1 to the telnetd.  When the session is
closed on the remote host, pt sends another SIGUSR1 to telnetd and exits.
telnetd would probably want to force renegotiation of the terminal type at
that point, as well.

Maybe I'll take a look at it .. I've been meaning to inspect the telnetd
sources for comparison, and because eventually I want to have a hacked Linux
telnetd which can accept 5250 sessions as well as vtxx sessions.  No promises,
tho... I'm not going to put much effort into a strange hackish request :-/

-Jay 'Eraserhead' Felice
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