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UDP Server periodically disconnects - 12.Nov.2009 1:20:19 PM

ducle

Posts: 24
Joined: 16.Jun.2002
Status: offline

I have opened port UDP 3074 for outbound and inbound two 2 access rules. I'm running ISA 2004 standard on a Windows 2003 SP1.

Rule 1 : UDP 3074 Send Receive
Publish Rule 2 : UDP 3074 Receive Send

Every so often at some time later (usually less than 30 minutes) the
server publisher stops working. I started doing wireshark on the nic and the inbound traffic is definitely still there. Then I started doing a 'netstat -an' and started to notice the nic:3074 UDP * listener disappears at the same time the published server stops working. I would have to disable and then re-enable the publish rule to get the server to receive inbound traffic again.

Has anyone seen something similar where UDP listeners stops listener for some reason? Any help would be appreciated.

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RE: UDP Server periodically disconnects - 12.Nov.2009 1:50:14 PM

Rotorblade

Posts: 1348
Joined: 27.Feb.2007
Status: offline

Did you define two protocols; one for each with diffrent names?

RB

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David Melvin
Ohio
MCSE: Security 2003, MCSA:Security 2003

(in reply to ducle)

Post #: 2

RE: UDP Server periodically disconnects - 12.Nov.2009 1:53:22 PM

ducle

Posts: 24
Joined: 16.Jun.2002
Status: offline

yes, two different protocols with different names. and two
different access rules with different names.

(in reply to Rotorblade)

Post #: 3

RE: UDP Server periodically disconnects - 12.Nov.2009 2:43:48 PM

Rotorblade

Posts: 1348
Joined: 27.Feb.2007
Status: offline

Ok thanks. Is your server being flooded with too many UDP packets?

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David Melvin
Ohio
MCSE: Security 2003, MCSA:Security 2003

(in reply to ducle)

Post #: 4

RE: UDP Server periodically disconnects - 12.Nov.2009 3:05:06 PM

ducle

Posts: 24
Joined: 16.Jun.2002
Status: offline

I do not believe it's being flooded. But, are you suggesting that
the IP stack maybe flooding and causing the UDP listener to drop
that port? It may very well be, I have to run some tests to find out.

(in reply to Rotorblade)

Post #: 5

RE: UDP Server periodically disconnects - 12.Nov.2009 3:32:51 PM

Rotorblade

Posts: 1348
Joined: 27.Feb.2007
Status: offline

quote:

But, are you suggesting that
the IP stack maybe flooding and causing the UDP listener to drop
that port?

yep, or ISA is dropping it. If you have IDS enabled, it could be considered an UDP bomb or attack? Anything showing in the ISA logs and Dashboard alerts? Non-TCP connections limits could be set to low?

http://technet.microsoft.com/en-us/library/cc302445.aspx

_____________________________

David Melvin
Ohio
MCSE: Security 2003, MCSA:Security 2003

(in reply to ducle)

Post #: 6

RE: UDP Server periodically disconnects - 14.Nov.2009 5:29:21 AM

ducle

Posts: 24
Joined: 16.Jun.2002
Status: offline

I checked the IP connections limits, they were set at defaults 1000 and 160. I increased them to 10000 and 16000, and the UDP listeners still disconnects
after a while. There were no alerts in the dashboard or alerts to indicate any
kind of instrusion. Then I ran wireshark on the port and during the times disconnect
happens, there was not much traffic going to the UDP listener. About 60 packets/second. At this point, I don't know where to look into next. If you
have any ideas I appreciate it.

(in reply to Rotorblade)

Post #: 7