Cached IP Address Never Expires for SNMP Trap Destination

• Microsoft Windows NT Workstation versions 3.5, 3.51, and 4.0
• Microsoft Windows NT Server versions 3.5, 3.51, and 4.0

SYMPTOMS

In the Simple Network Management Protocol (SNMP) Service Configuration, the trap destination can be entered as a host name or IP address. The host name is resolved to an IP address when the SNMP Agent loads, and is cached until the computer with the SNMP agent is restarted, or the SNMP service is stopped. This cached address is only used by SNMP; other services will do a name query to find this IP address.

If the SNMP Agent is configured to send traps based on host name, and the IP address changes on the SNMP Management Station at some point after the SNMP Agent is started on the Windows NT computer, the trap would not be received.

WORKAROUND

If host names are used for trap destinations, and the IP address of a Network Management station changes, be sure to stop and restart the SNMP service on the Windows NT computer. The SNMP service can be stopped and started by using the Services tool in Control Panel, or by typing net stop SNMP and net start SNMP at the command line.

You can also use an IP address for the trap destination; and modify this address if needed.

STATUS

Microsoft has confirmed this to be a problem in Windows NT. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.