RE: Telnet sessions disconnecting -- Any Solution yet? -- MIDRANGE-L

On Mon, 22 Jul 2002, Chris Whisonant wrote:

> Anyway, there are no other sites I'm seeing with this (out of about 25
> remote locations!) This site is the only one that is on a cable modem setup
> using VPN. All other sites have a T-1 or faster link back to our
> headquarters while the cable modem is on a separate network (thus needing
> the VPN tunnel). Our network guy is saying that the tunnel has been up for
> 16 days and he's not seeing anything here. However, if this is the only
> workgroup with these symptoms, how can it be the AS/400. We have about 800
> users and only the five at this location are losing their session.

We also had this problem happen a lot.  We've changed some settings on the
iSeries and now it happens much less often.  Of course now I don't
remember what settings.  I'll check when my boss gets back.

Here are reasons why I really do believe the AS/400 is screwing up:

1.  As I already mentioned, changing some settings on the AS/400 helped.
2.  We connect to a customer over the internet.  We use Client Access and
tn5250 to connect to their AS/400.  We use ssh to connect to their linux
gateway (which is immediately in front of the AS/400).  Before we made the
changes to the AS/400, Client Access dropped quite often.  tn5250 dropped
once.  ssh *never* dropped.

So either Windows sucks, or Client Access, or the AS/400.  tn5250 (running
on linux) dropped once, so maybe Windows doesn't network very well.  ssh
never dropped (even when 5250 sessions were dropping at the same time) so
I don't believe there was ever a general networking problem.

Here are some ideas:

What is common among all the sessions drops?  I bet that everyone on this
list who is experiencing dropped sessions is running Client Access on
Windows.  Anyone losing sessions who isn't using Client Access on Windows?
Also common is that sessions are dropped only when they are remote over
the internet.  This points to some kind of latentcy somehow interfering.
We never saw unacceptable latentcy times or bandwidth restrictions.  Yet
sessions were still lost.  Perhaps the slightly larger latentcy causes
occasional yet unrecoverable timing problems.

What is not common?  Well it doesn't seem to matter what release of OS/400
you use.  We had problems with V3R7.  People are reporting problems with
V5R1.  So that doesn't seem to make a difference.  The type of router used
doesn't seem to matter, either.  We use Cisco, Netgear, 3com, and linux
for all our routing and networking.

Here is something to try:  Use a plain telnet session to connect instead
of client access.  See if that drops.  Try different OSes (on the client
end).  As previously stated, my tn5250 sessions and ssh connections on
linux kept right on chugging even when the sessions of the guy next to me
were failing.

James Rich