Re: Sessions dropping -- MIDRANGE-L

Can you post your TCP Keep Alive value (from CHGTCPA),
your Telnet timeout values(CHGTELNA), and your inactive job system
values(DSPSYSVAL)?
also verify some network device/server not on a scheduled reboot (like i
have a customer who
reboots their Terminal Server every day on her way out the door (and drops
any remote users)..
jim
----- Original Message ----- 
From: "Uros Davidovic" <Uros_Davidovic@xxxxxxxxxxx>
To: "Midrange Systems Technical Discussion" <midrange-l@xxxxxxxxxxxx>;
"Scott Klement" <klemscot@xxxxxxxxxxxx>
Sent: Thursday, September 11, 2003 9:38 AM
Subject: Re: Sessions dropping


>
> >
> > > We have had users that have had session drop for no apparent reason.
> > The
> > > sessions go to a black screen, the 400 job is still out there and it
> > the
> > > old "session stopped per request from the device" message is in the
> > > joblog. It seems to happen at approximately the same time every day
> > and
> > > all of the TCP settings look fine.
> >
> > Is there something that runs at that time every day?
>
> Not to the best of my knowledge. The network folks cannot think of
> anything and there is nothing on the iSeries.
> >
> > > The only change to the network setup was a recent change to the DHCP
> > > service (details of which I do not know)  and even session that are
> > > configured to go to the actual IP, not the name, drop.
> >
> > This could be a DHCP issue.   The PC may be having it's lease revoked
> > at
> > that time every day.
> >
> Actually, I understand the difference, even though it may not be evident
> from the statement. Going through the archives before posting this, I did
> find the DHCP lease expiration issue on a similar post and trying the
> name vs. the IP was because one of the network folks mentioned they did
> not have a internal DNS server. Just wanted to see if it made a
> difference and if the dropping sessions would have anything in common,
> like they are all setup to connect to a name.
>
> > Based on this statement "even session that are configured to go to the
> > actual IP, not the name, drop"  it appears that you have gotten DHCP
> > and
> > DNS confused.
> >
> > DNS takes a name, and converts it to an address.   If something would
> > change with DNS, it would not affect clients that are connecting
> > directly
> > with the IP Address.
> >
> > DHCP, however, is what assigns the PCs their IP addresses (often based
> > on
> > the Ethernet MAC address) and has nothing to do with the names at all.
> > If DHCP is making the computers change their IP address, you'll have
> > the
> > problem that you've described above.   Why?  Because the TCP connection
> > that the TN5250 session is running in relies on two sets of addresses,
> > one
> > for the PC and one for the AS/400.  If one or the other of those
> > addresses
> > changes, the connection will stop working and eventually time out.
> >
> >
> > > I tested 4 sessions on one PC, two dos telnets to name and IP and two
> > CA
> > > sessions to IP both and only one session dropped... Per the network
> > > folks, there is no inactivity/latency setting on the router that
> > these
> > > go to...
> >
> > As I said, this could be happening when the DHCP lease is renewed, if
> > the
> > PC stops communicating with the iSeries for a second, and that happens
> > to
> > be when the iSeries sends it's keepalive packet, it'll reset.
> >
> > I was thinking also that the PC might be resetting it's TCP stack at
> > that
> > time, but if some of the sessions are surviving, then that's not the
> > case.
> >
> > >
> > > Any clues?
> > >
> >
> > Try changing the DHCP lease time to be an hour or two longer and see if
> > that helps, or changes what time the disconnects happen.   If they
> > start
> > happening an hour later, you know that the DHCP lease is where the
> > issue
> > is.
> >
> > If that doesn't help, then you may have a hardware problem.   Not sure
> > why
> > that would happen at a regular interval, but it might be due to a power
> > fluctuation or something that happens at that time every day.
> >
> > That's all I can think of, right now.
>
> I also thought of a hardware problem, but the problem is sporadic and
> happens to a lot of PCs. The only thing in common is the router, as I
> said, but per the network folks it has been up for days with no issues
> that they can see...
>
> I will see if I can try the static IP thing and see what the lease
> expiration interval is, there probably is one, due to the security
> restrictions the company has.
>
> Thanks for the help, Scott...
>
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