RE: Troubleshooting interrupted Telnet connections

One problem I have run in to also is local firewalls, that is the PC
running the tn5250 application firewall. OS400 keep alive uses a
different connection I think to see if the remote client is still there.
I know if I have the State full firewall enabled with my Cisco VPN
client, my tn5250 sessions drop. We have

Change TCP/IP Attributes (CHGTCPA)

Type choices, press Enter.

TCP keep alive . . . . . . . . . TCPKEEPALV 10

And we have:
Change TELNET Attributes (CHGTELNA)

Type choices, press Enter.

Autostart server . . . . . . . . AUTOSTART *YES
Number servers . . . . . . . . . NBRSVR *CALC
Session keep alive timeout . . . TIMMRKTIMO 120

The first is in minutes and the second is in seconds.




Chris Bipes
Director of Information Services
CrossCheck, Inc.

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of John.BresinaJr
Sent: Friday, April 23, 2010 8:42 AM
To: Midrange Systems Technical Discussion
Subject: RE: Troubleshooting interrupted Telnet connections

James,

We were having a similar issue here. I contacted IBM and after running
some TCP/IP traces from the IBM 'I' we found that the system was being
sent a RST 'RESET' request from the network. I then contacted our
network team and found that they have 5 minute inactivity timers set on
the routers/load balancer that my system is attached to. So when I
looked at the CHGTELNA command and looked at the Session Keep Alive
Timeout ...TIMMRKTIMO parameter it was set to *CALC. Apparently *CALC
equates to about 10 minutes. I changed that parameter to 240 seconds or
4 minutes so the system sends a "I'm here" message to the network to
avoid their 5 minute inactivity timeout. After changing that parameter
you also need to Stop and restart Telnet services. Now we no longer
have the issue of our users sessions timing out when they are on the
phone or on another application.