RE: 5250 sessions killing the system

I have not read every single response to this thread, but we have once or
twice a year had auto-connect or auto-reconnect of either Client Access 5250
sessions or 5250 attached printers that will swamp our system - until we
figure out the device and vary off, and appear as thousands of attempts. We
always solved it at the pc itself.

Jim Franz


-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxxxxxxxx] On Behalf Of
Rob Berendt
Sent: Thursday, November 14, 2019 2:45 PM
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxxxxxxxx>
Subject: RE: 5250 sessions killing the system

Been going on for 2-3 weeks.

Rob Berendt
--
IBM Certified System Administrator - IBM i 6.1 Group Dekko Dept 1600 Mail
to: 2505 Dekko Drive
Garrett, IN 46738
Ship to: Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com


-----Original Message-----
From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of Jeff
Crosby
Sent: Thursday, November 14, 2019 2:28 PM
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxxxxxxxx>
Subject: Re: 5250 sessions killing the system

CAUTION: This email originated from outside of the organization. Do not
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Did this just start today? Bizarre.

On Thu, Nov 14, 2019 at 2:15 PM Rob Berendt <rob@xxxxxxxxx> wrote:

They also said that I may want to turn off auto reconnect on those

clients.

Rob Berendt
--
IBM Certified System Administrator - IBM i 6.1
Group Dekko
Dept 1600
Mail to: 2505 Dekko Drive
Garrett, IN 46738
Ship to: Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com


-----Original Message-----
From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of Rob
Berendt
Sent: Thursday, November 14, 2019 2:06 PM
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxxxxxxxx>
Subject: 5250 sessions killing the system

I have this case opened with IBM. There are certain clients attaching to
the system where it starts 10,000+ port 23 (telnet) connections to our
system. All using the same 1-3 workstation id's. Totally blows our
activity level out of the water and is quite an effective denial of

service

attack.

-- Some TCP connections do not spawn "jobs". Therefore we'll use a
different service.
select local_port, remote_address, count(*) as nbrconnections
from gdihq.qsys2.NS_INFO
where local_port = 23
group by local_port, remote_address
having count(*) > 10
;

Messing with things like QAUTOCFG, QAUTOVRT has ZERO effect on stopping
this.

IBM's reply has been basically put on a patch to that version of the
deprecated Client Access or upgrade to iACS.

Since most of these are Windows 7 VM sessions our Windows admins are
leaning towards the patch. When they are ready to upgrade to Windows 10

on

the 'gold' image they'll upgrade to iACS.

Rob Berendt
--
IBM Certified System Administrator - IBM i 6.1
Group Dekko
Dept 1600
Mail to: 2505 Dekko Drive
Garrett, IN 46738
Ship to: Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com

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Jeff Crosby
VP Information Systems
UniPro FoodService/Dilgard
P.O. Box 13369
Ft. Wayne, IN 46868-3369
260-422-7531
direct.dilgardfoods.com

The opinions expressed are my own and not necessarily the opinion of my
company. Unless I say so.
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