About Private IP Addresses

When you configure a trusted or optional interface, we recommend that you use an IP address in one of the three IP address ranges reserved by the Internet Engineering Task Force (IETF) for private networks on LANs.

  • 192.168.0.0/16
  • 172.16.0.0/12
  • 10.0.0.0/8

By default, the Firebox enables dynamic NAT for outbound traffic from addresses in these ranges to any external interface.

For more information about dynamic NAT, go to About Dynamic NAT.