Figure 3. New blocking rule for SNMP to only accept from 20.2.61.0.

# ipfw -n list b
Type    Proto        From                 To             Ports
deny    udp   anywhere            192.168.1.1/32      any -> any
deny    udp   anywhere            20.2.51.105/32      any -> any
accept  udp   anywhere            20.2.51.105/32      domain -> any
accept  udp   anywhere            20.2.51.105/32      any -> snmp
deny    tcp   anywhere            20.2.51.105/32      any -> any
deny    tcp   anywhere            192.168.1.1/32      any -> any