The tmnxNatPlAddrFree notification is sent when a range of outside IP addresses becomes free at once. The range starts at address tmnxNatNotifyOutsideAddr and ends with address tmnxNatNotifyOutsideEndAddr. It replaces a number of tmnxNatPlBlockAllocationL2Aw or tmnxNatPlBlockAllocationLsn notifications; the allocated port blocks associated with each IP address in the indicated range are released. The reason why this address range is released, is described in the tmnxNatNotifyDescription. If the value of tmnxNatNotifyInsideVRtrID is not equal to zero, it means that only the port blocks associated with hosts in that particular virtual router instance are released; if the value of tmnxNatNotifyInsideVRtrID is equal to zero, it means that all the port blocks are released.
Sources for this description
Multiple manufacturers; see the original MIB MIB copies (LibreNMS/Observium Community)Netdisco MIB archive copiesNokia networking MIB copies (LibreNMS/Observium Community)