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Setting the MOM Agent to Receive SNMP Traps

 

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MOM allows administrators to configure agents to send SNMP traps when an event, alert or other condition occurs.  For example an SQL Server might be configured to send an SNMP trap when the SQLSERVERAGENT service stops.  This response is selected from the standard MOM responses and is relatively simple to set up.

More difficult is configuring a MOM agent to listen for SNMP traps and respond accordingly.   This is because the MOM functionality depends on WMI's support for SNMP which is not installed by default either with MOM or with Winnt, Win2k or XP.

The basic steps are as follows:

1.) Install SNMP on the machine running the MOM Agent.  Make sure it is part of the same SNMP community being used by the system that is the source of the SNMP traps.  By default all systems belong to the 'public' community.

2.) Install the WMI SNMP Provider on the machine running the MOM agent

Windows XP: Use the following instructions to install the SNMP provider.

  1. From Control Panel, select Add/Remove Programs.
  2. Select Add/Remove Windows Components, then in the Windows Components Wizard, select Management and Monitoring Tools.
  3. Select Simple Network Management Protocol and WMI SNMP Provider, then click OK.
  4. Follow the steps in the wizard to complete the installation.

Windows 2000: Run the SNMP provider Setup program, Wbemsnnp.exe, from the System32\wbem directory or the \i386 directory of the Windows 2000 installation CD.

Windows NT version 4.0: Install the SNMP provider when installing the WMI core or from the Internet at http://www.microsoft.com/downloads.

Windows 95/98: The SNMP provider cannot be installed or run on this operating system.

3.) Create an Event Processing rule using one of the two SNMP Trap Catcher providers supplied with MOM.   The two providers are 'SNMP Trap Catcher' and 'SNMP Extended Trap Catcher' and can be selected from the default available list.  Either of these two data providers will respond to the arrival of an snmp trap but they report the data differently.  The 'SNMP Trap Catcher' reports snmp v1 format and the 'SNMP Extended Trap Catcher' reports snmp v2 format.

As they stand, the snmp trap catchers only report the EXISTENCE of the trap i.e. it's arrival.  No test is done for where the trap came from or what information it carries.  To do this the MOM administrator must create their own snmp trap catchers.

These are examples of Extrinsic events in WMI and have the advantage of not having to be constantly polled in WMI.  The only activity takes place when the trap arrives.