SCOM 2007 R2

SNMP port claimed, but not by the snmp services.

Posted by rob1974 on October 24, 2013


I recently came across the following issue. SCOM was throwing errors every minute and auto closing them fast from this monitor: Network Monitoring SNMP Trap port is already in use by another program. 2 things I notice when I looked at it. The first one was it was a manual reset monitor how can that be auto closed? And the second one, it was about the management server itself and it’s inability to claim the SNMP trap receiver port (UDP 162), while I was sure I had disabled the SNMP services.

So what claimed the SNMP port? With 2 simple commands you can find out:

> netstat –ano –p UDP| find “:162”.

This resulted in some PID. Now check the PID versus tasklist /svc and we should have the process responsible for the claim.

> tasklist /svc /fi “pid eq <pidnumberfound>”

and it returned nothing.

After quite some rechecking my results in different ways I came to the conclusion that the UPD port really had been claimed by an process that didn’t exist anymore. I feel that’s it is some bug in Windows server, it should always close the handles whenever a process dies, but let’s be pragmatic about it > reboot server. After the reboot I ran the commands above again to find out the “monitoringhost.exe” claimed the port. W00t we solved the problem, SCOM can receive traps again.

As mentioned in the start of the post. The alerts were closing fast. And because of that fact, if someone saw it they wouldn’t pay any attention to it. SCOM wasn’t receiving any traps in the above condition, so why was the alert of a manual reset monitor being auto closed fast?

The explanation is quite simple: the recovery task for this monitor. This recovery task runs and disables the Windows SNMP services and will do a reset of the monitor. The problem with this is that the recovery didn’t do anything (the SNMP services were already disabled), but it did reset the monitor.

I think the solution should be rewrite of the monitor, where the monitor checks if SCOM really has claimed the SNMP port. I could do this, but for now I will leave it. It might have just been one of those exotic errors you’ll see once in a lifetime…


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