IBM Tivoli Network Manager stores all snmp passwords in ncim. snmp version 1 and 2 passwords are moved to snmpV1Sec. snmp version 3 passwords are moved to snmpV3Sec. But how do you find which password was used successfully in the discovery?
The starting place for consistency is to use OQL. Whether your ncim database is DB2, Oracle, Informix or Mysql the OQL connection from the ITNM server is the best.
Documentation on NCIM OQL query