1. Navigate to Services | SNMP.
2. Check the Enable SNMP Daemon checkbox, as shown in the following screenshot:

3. Leave the Polling Port set to the default value of 161.
4. Optionally, enter a location and contact name in the System Location and System Contact edit boxes.
5. In the Read Community String edit box, enter a passphrase. This string is roughly equivalent to a password, restricting access to querying SNMP to devices specifying the correct community string.
6. In the SNMP Modules section, specify the modules to be queried by checking the appropriate checkboxes.
7. In the Interface Binding section, choose the interfaces on which to listen (the default value is All).
8. When you are done making changes, click on the Save button.

By enabling SNMP on pfSense, the system can now query vital SNMP information from different SNMP agents.