134 Chapter 5 Advanced IP configuration300868-GConfiguring address translationAddress translation allows the Instant Internet unit to route traffic that has privateor reserved IP addresses to and from the Internet. Instant Internet can isolate yourLAN from the Internet by performing address translation on routed packets,which enables it to translate workstation addresses into legal IP addresses. IPaddress translations are totally transparent to workstations on the LAN.Some of the benefits of using Instant Internet as an address translator include:• Translating addresses transparently.• Simplifying the administrator’s task by allowing existing, private addressingschemes to be used while still allowing Internet access.• Acting as a firewall.If the Instant Internet unit is currently running address translation and is logicallyinstalled between the servers you want to be public (for example, Web servers ormail servers) and the Internet, then you must add provide some additionalconfiguration. See “Publishing a private server” on page 135.Disabling address translationWhen Instant Internet hardware and software are installed, output addresstranslation is automatically enabled as a default for your unit. However, if you areusing IP forwarding, you should disable address translation. For more informationon IP forwarding, refer to “Configuring IP forwarding” on page 130.To disable address translation:1 Start Setup, and if prompted, select a unit to configure.2 In the Interfaces area, select your WAN interface in the list and then clickConfigure.The Configuration dialog box opens (Figure 64).
