IP Passthrough is a useful feature if a host computer or server on the Local Area Network needs to have access into it from the internet with a real public IP address. With IP Passthrough configured, all IP traffic, not just TCP/UDP, is forwarded back to the host computer. This can be necessary with certain types of software that do not function reliably through Network Address Translation.

In this configuration, the local PC will share the Public IP addressing information with the WAN side of the router. Also, this computer will have access to other resources on the LAN while it is in this mode.

This technote will guide you through the setup process for IP Passthrough in your ENT-Series Netopia.

Firmware References:

• v8.3.1   (and up) - ENT-Series

Before You Start

Telnet into the Netopia router's menu interface at 192.168.1.1 (if using the default IP setting). If your network has a different IP addressing scheme, modify this accordingly.

The Netopia Telnet Menu Interface

IP Passthrough Configuration:

1. From the Main Menu, arrow down and enter WAN Configuration...
2. Enter on the WAN Setup... field.
3. On the WAN Configuration screen, arrow down and enter NAT Options...


NAT Options Selection

4. Use the tab key to toggle the IP Passthrough Enabled: to Yes and hit enter. (You must hit the enter key to retain this change!)


Enable IP Passthrough Option

5. Press the escape key to return to the Main Menu.
6. Arrow down and enter Utilities & Diagnostics... and Restart System...
7. CONTINUE to confirm this action.
8. After the Netopia restarts, you will have the ability to use a public IP on a local workstation while that address is also used as the WAN IP of the router.
9. Now you will need to assign that public IP address into the Internet TCP/IP properties of the computer.
10. If you are unsure of the current public IP address of the Netopia, follow these steps:
    1. From the Main Menu, arrow down to Quick View...
    2. If your internet service is ADSL or PPPoE, look under Current WAN Connection Status. You can see your public IP address on the Profile Name line underneath More Info.
    3. If this is an Ethernet-to-Ethernet router, you can see the IP address on the Ethernet WAN1: line underneath IP Address.

11. Enter this public IP into the TCP/IP properties of the computer.


The Netopia Public IP Address

Conclusion

You have now configured your router for IP Passthrough.