The Enterprise Manager (EM) is setup to notify a remote application via SNMP traps. The traps are received, but the OID identifier for the EM (188.8.131.52.4.1.10480.1.1.xxxx - where xxxx is the identifier for the EM) changes whenever the EM is restarted. As a result, it is impossible to determine which EM is sending the trap in a multi-EM environment.
The OID for the EM is saved in an xml file in the folder <EM_HOME>/config/internal/server/snmp. When it is not present (which can occur when a MIB is not published), the EM's OID is randomly recreated when the EM is restarted.
This problem can be fixed by generating a MIB file. To create a MIB file: