| 9.2 |  | Network Address Translations |
| 9.2.4 |  | Dynamic outside translations |

| Overview of dynamic outside translations If inside translations refer to the translation of the IP address of an inside host to that of an acceptable outside IP address, then it stands to reason that outside translations refer to the translation of the IP address of an outside host to that of an acceptable inside IP address. Dynamic outside NAT enables the PIX Security Appliance to translate a host address on a less secure interface to a defined address on a more secure interface by using the global command.

Dynamic outside NAT is useful for simplifying router configuration on the internal or perimeter networks by controlling the addresses that appear on these networks. In Figure , the outside NAT configuration eliminates the need for a route to network 172.26.26.0 on Router C. Source addresses of packets inbound from network 172.26.26.0 are translated to IP addresses from the 10.0.0.20 to 10.0.0.254 range. The access list ACLIN works with static mapping to permit hosts on the 172.26.26.0 network to access the FTP server at 10.0.2.2.

Please view the Online Command Reference for an introduction to the nat command and examine its syntax.