2000-A2-GB20-10 - 171 - February 2004A significant advantage of NAT is that you can configure it withoutchanging hosts or routers, other than those few routers on which NAT isconfigured. NAT multiplexes internal network traffic and presents it to theInternet as if it is from a single source with one IP address.To configure NAT, complete the following steps: Enable NAT translation by port (following) Configure the NAT local server (page 172) Configure NAT TCP or UDP timeouts (page 173) Configure the NAT port range (page 174)When you have completed these four tasks, reset the IAD for the newconfiguration to take effect. NAT is now fully operational.EnablingNATTranslationEach IAD is configured with NAT disabled. To enable NAT translation:1. Type P on the NAT Configuration menu to display Enable/Disable NATTranslation by Port.2. If at least one virtual circuit on the WAN exists, and the LAN port is alsoconfigured with an IP address, or more than one PVC/DLCI exists, theIAD displays the interfaces (sample following) on this IAD.Available Interfaces:1. G2237 xDSL2. 10/100BaseT Ethernet0. (Abort)3. Otherwise, the IAD displays the WAN port table and prompt:Port VPI VCI Encapsulation Type PCR Service1 0 40 RFC 1483(LLC Encapsulation) 0 UBR2 0 41 RFC 2364(PPPoATM-VC Muxing) 1207UBR3 0 101 RFC 2364(PPPoATM-VC Muxing) 1207UBR--------Total = 2414 cpsMaximum PCR this interface can support = 1207 cpsSelect Port: [1-8]Type the port number on which to enable NAT and press Enter.4. The IAD displays the following:NAT Translation for this port is currently DISABLEDEnter E to Enable, D to Disable: e5. Type E to enable NAT, or D to disable NAT.6. The IAD saves the setting and displays the NAT Configuration menu.7. Continue with other NAT configuration tasks, or press Escape to returnto the Main menu.8. Reset the IAD (page 14) when you finish configuring NAT.
