Auto log on to a mainframe using telnet

["York, Albert" <albert.york@xxxxxxxxxxxxxx>]

A couple of weeks ago I posted a message about connecting to a mainframe
from an AS/400 using telnet 3270 and automatically logging on. From the
responses I received, there didn't seem to be a way to do so.

For reasons that I won't go into here, it was imperative that I find a way
do to this. Eventually, I did figure out a way and I wanted to share it in
case it might be useful for others.

I wrote a small sockets program which listens on port 923 and connects to
the telnet port (23) on the mainframe. The program that the user runs on the
AS/400 uses telnet 3270 to connect to port 923 at address 127.0.0.1.Most of
the time the sockets program simply passes data back and forth between the
two sockets. However, when it finds a string which contains the mainframe
logo on prompt, it sends the log-on string to automatically log on the user.

Obviously, there is additional overhead, but for us that is an acceptable
tradeoff.

Albert York