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Portscan !!

I have seen the telnet being invoked by portscan and then leaving the 5250
idle and just wait for timeout.

And if it is not a port scan, then it can be anything similar.

On Tue, Jun 6, 2017 at 10:58 AM Gad Miron <gadmiron@xxxxxxxxx> wrote:

Perhaps some PC/Server on the net was accidentally allocated an IP address
(DHCP)
that collided with your i server?

Gad




date: Mon, 5 Jun 2017 18:21:43 +0000
from: "Steinmetz, Paul" <PSteinmetz@xxxxxxxxxx>
subject: What would cause hundreds of 5250 sessions all start
dropping, from multiple LPARs

We have a reoccurrence of this issue, started about an hour ago.
We never found the root cause.
Possibly an issue with PC obtaining a new lease when their current lease
expires.
Not 100% confirmed.

Paul


-----Original Message-----
From: Steinmetz, Paul
Sent: Wednesday, February 08, 2017 4:18 PM
To: 'Midrange Systems Technical Discussion'
Subject: RE: What would cause hundreds of interactive users all start
dropping, from multiple LPARs

Interesting find

PC obtained a new lease shortly before the CPF5140 was posted.
I'm not a network person, but could there have been an issue with leases
expiring and being renewed?

CPF5140 Diagnostic 70 02/07/17 13:30:55.498675

Paul



-----Original Message-----
From: Steinmetz, Paul
Sent: Tuesday, February 07, 2017 4:43 PM
To: 'Midrange Systems Technical Discussion'
Subject: RE: What would cause hundreds of interactive users all start
dropping, from multiple LPARs

Started at 12:45.
Multiple iSeries LPARs - Pencor05, Pencor06, Pencor07, Penco08 My
connections to 4 different LPARS, 3 different NICS, all at the same
time.
Not all users at once.
About 20 every minute.
Each user only once (so far)
No entries in any logs. PAL, LIC, QHST

Problem appears to have stopped around 14:25.
iSeries performance graph showed high number of TCP connection resets
during the 12:45 thru 14:25 problem window.

from 3 LPARS, 3 different NICs
Appears that only 5250 Client Access and GUI was impacted (PC traffic).
from 3 LPARS, 3 different NICs All other applications (hundreds)
connecting
to both internal and external remotes were fine.

Possibly an issue with QTVDEVICE jobs ???

CPF5140 Diagnostic 70 02/07/17 12:45:56.790988
QWSERROR QSYS 0630 QWSGET QSYS 067C
Message . . . . : Session stopped
by a request from device QPADEV004S.
CPF5503 Diagnostic 30 02/07/17 12:45:56.791059
QWSERROR QSYS 0652 QWSGET QSYS 067C
Message . . . . : Input or Output
request failed. See message CPF5140.

Paul

-----Original Message-----
From: Steinmetz, Paul
Sent: Tuesday, February 07, 2017 2:06 PM
To: 'Midrange Systems Technical Discussion'
Subject: RE: What would cause hundreds of interactive users all start
dropping, from multiple LPARs

Problem still occurring.
Started at 12:53.
Not all users at once.
About 20 every minute.



-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Ken Meade
Sent: Tuesday, February 07, 2017 1:45 PM
To: Midrange Systems Technical Discussion
Subject: RE: What would cause hundreds of interactive users all start
dropping, from multiple LPARs

We saw something similar a few years ago. Turned out it was a glitch in
an
addressing table in one of our switches.

-----Original Message-----
From: James H. H. Lampert [mailto:jamesl@xxxxxxxxxxxxxxxxx]
Sent: Tuesday, February 07, 2017 1:40 PM
To: Midrange Systems Technical Discussion
Subject: Re: What would cause hundreds of interactive users all start
dropping, from multiple LPARs

On 2/7/17, 10:34 AM, Steinmetz, Paul wrote:
What would cause hundreds of interactive users all start dropping,
from
multiple LPARS

Massive communications glitch?

--
JHHL


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