Steps to reproduce:

1. Add monitoring of a pfSense host using the app/pfsense_snmp template
2. Wait for data
3. Compare value of system uptime in Zabbix and what's shown in the pfSense GUI

Result:
**

System uptime data in Zabbix shows how long the snmpd on the pfSense host has been running.

Expected:

System uptime data in Zabbix should show how long it has been since the pfSense host booted.

The solution is to use HOST-RESOURCES-MIB::hrSystemUptime.0 instead of DISMAN-EVENT-MIB::sysUpTimeInstance.

Patch against master is attached.