Final answer:
A network management server is responsible for collecting diagnostic and monitoring data from networked devices, using protocols like SNMP to assist network administrators with maintaining a network's health.
Step-by-step explanation:
The type of server used to collect diagnostic and monitoring data from networked devices is the network management server. Unlike a web server, database server, or application server which serve different purposes in a network architecture, a network management server specifically focuses on the management and monitoring of the network's hardware and software. Through the use of network management protocols like Simple Network Management Protocol (SNMP), these servers can gather performance data, alert network administrators about malfunctions, and provide valuable information for troubleshooting and ensuring the network remains operational and efficient.