Multi-NAT 4-27
IP Passthrough
Motorola Netopia® Embedded Software Version 8.7.4 offers an IP passthrough feature. The IP passthrough
feature allows for a single PC on the LAN to have the router’s public address assigned to it. It also provides PAT
(NAPT) via the same public IP address for all other hosts on the private LAN subnet. Using IP passthrough:
•The public WAN IP is used to provide IP address translation for private LAN computers.
•The public WAN IP is assigned and reused on a LAN computer.
•DHCP address serving can automatically serve the WAN IP address to a LAN computer.
When DHCP is used for addressing the designated passthrough PC, the acquired or configured WAN
address is passed to DHCP, which will dynamically configure a single-servable-address subnet, and reserve
the address for the configured MAC address. This dynamic subnet configuration is based on the local and
remote WAN address and subnet mask. If the WAN interface does not have a suitable subnet mask that is
usable, for example when using PPP or PPPoE, the DHCP subnet configuration will default to a class C
subnet mask.
Note: Globally, only one dynamically-configured DHCP subnet is available. If you configure multiple Connection
Profiles to use IP Passthrough's DHCP option, when any of these profiles is established, the dynamic DHCP
configuration will be overwritten. IP passthrough is restricted to the primary LAN.
In the case of an Ethernet WAN router the IP passthrough configuration is located in the WAN Ethernet
Configuration menu. For all other routers, it is located in the Connection Profiles' IP Profile Parameters.
The WAN Ethernet Configuration screen, found under the WAN Configuration menu, WAN Setup screen,
appears as shown.
The IP Profile Parameters screen, found under the WAN Configuration menu, Add/Change Connection Profile
screen, appears as shown.
WAN Ethernet Configuration
Address Translation Enabled: Yes
Local WAN IP Address: 0.0.0.0
NAT Map List... Easy-PAT List
NAT Server List... Easy-Servers
NAT Options...
Stateful Inspection Enabled: No
Filter Set...
Remove Filter Set
Enable PPP over Ethernet: Off
WAN Ethernet Speed Setting... Auto-Negotiation
Wan Ethernet MAC Address: 00:fc:de:fa:dd:02
DHCP Client Mode: Standards-Based
RIP Options...
Set up the basic IP attributes of your Ethernet Module in this screen.