SNMP is another application-layer protocol supported by pfSense. SNMP collects and organizes information about managed devices, and is often used to monitor network devices. SNMP-managed networks consist of managed devices, software running on the managed devices (known as agents), and software running on the manager, known as a the network management station (NMS). Management data is organized hierarchically in structures known as management information bases (MIBs).

Enabling SNMP in pfSense will allow it to act as a network-management station, and this will enable you to monitor network traffic and flows, pfSense queues, as well as system information (for example, CPU, memory, and disk usage). It is also capable of running traps on managed devices that are triggered by certain events. SNMP is implemented under pfSense with the bsnmpd service.

It contains the most basic...