cmTrapDestinationPort is the UDP port number the system uses when sending traps to a given receiver, forming the second part of the trap-destination table's index alongside cmTrapDestinationIpAddr, with 162 being the standard SNMP trap port. An administrator configures this to match whatever port the receiving trap collector is actually listening on. For example, if an NMS is configured to listen for traps on a non-standard port instead of 162, the operator would set cmTrapDestinationPort accordingly for that receiver's table entry.