On which port does an SNMP agent listen for requests?

The correct answer is that an SNMP agent listens for requests on UDP port 161. SNMP, or Simple Network Management Protocol, is designed to facilitate the management and monitoring of network devices.

UDP port 161 is specifically designated for the SNMP request messages sent from the management system (the SNMP manager) to the SNMP agent on managed devices. This port is essential for initiating communication, allowing the management system to request information such as device status, performance statistics, and configuration details from the SNMP agent.

Using UDP for SNMP requests is appropriate because it is a connectionless protocol, which allows for faster transmission of messages without the overhead of establishing and maintaining a session. This is critical in network environments where timely data collection is necessary.

Understanding this port designation helps in network configurations and security settings, ensuring that management systems can effectively communicate with network devices using SNMP for monitoring and control purposes.