Simple Network Management Protocol - monitoring devices across the network

The Simple Network Management Protocol is used to monitor and control computers and network devices. An agent runs on each monitored device and determines its status. A central Network Management System (NMS) requests and collects this data. When an agent detects a serious event, it sends a trap packet to the NMS on its own, so the administrator is informed promptly. Traps can also be sent as informs, which the NMS has to acknowledge.

SNMPv1 and SNMPv2c transmit the password — known as the community — unencrypted. SNMPv3 adds user authentication and encryption and offers graded security levels: no authentication, authentication only, or authentication combined with encryption (authPriv). In security-critical environments, SNMPv3 with a high security level is recommended.