Final answer:
The service that will receive the trap is SNMP (Simple Network Management Protocol). SNMP is a protocol used by network devices to manage and monitor their operations.
Step-by-step explanation:
The service that will receive the trap is SNMP (Simple Network Management Protocol).
SNMP is a protocol used by network devices to manage and monitor their operations. When a managed port goes down on a network device, it generates an event and sends a trap message to a central management server. This server receives and processes the trap, providing information about the network device's status and allowing administrators to take appropriate actions.
Some examples of SNMP-based network management systems include Nagios and Cacti. These systems can receive and analyze SNMP traps, allowing network administrators to effectively monitor and troubleshoot their networks.
When a managed network device experiences an event where one of its managed ports goes DOWN and sends a UDP trap message to a central management server, the service that receives this trap is known as Simple Network Management Protocol or SNMP. None of the other options listed, such as DHCP (Dynamic Host Configuration Protocol), DNS (Domain Name System), or POP3 (Post Office Protocol 3), are used for receiving traps. SNMP is specifically designed to manage network devices and handle events and notifications like the situation described.