Lenovo 70BJ9005WW Configuring Port Forwarding on Double NAT Networks, Bridging the Primary Router

Hardware Management

Configuring Port Forwarding on Double NAT Networks

If for some reason the network configuration cannot be changed and your setup requires the double NAT, you must perform the port forwarding steps twice. On the primary router, set the port forwarding to the cascaded router's external IP address. On the cascaded router, set the port forwarding to the px4-300r's IP address.

Bridging the Secondary Router

Make sure that the primary router (usually the one connected to or acting as the DSL/Cable modem) is the only one with DHCP (Dynamic Host Configuration Protocol) and NAT (Network Address Translation) enabled. The secondary should be changed to bridging mode. Ensure that the secondary router connects to the primary router using a standard port rather than the port labeled Uplink or internet. This turns your secondary router into a switch; however, you can still enable its Wireless Access Point if so equipped.

Refer to the documentation that came with your router for configuration information and settings.

Bridging the Primary Router

If none of the above options are available, you must enable transparent bridging on your primary router. This may require contacting your ISP (Internet Service Provider) to configure the DSL or Cable Modem/NAT into bridge mode, which then disables the first NAT/Firewall. After this first firewall in the modem is disabled, the secondary router handles all the network traffic, Port Forwarding, and allows Remote Access to work.

You should not attempt bridging without help from the ISP. If bridge mode is attempted by the customer and not configured properly, it can render the customer's internet connection inoperable. Primary router bridging may also require special configuration information and settings on the secondary router.

If you configured your px4-300r using DHCP, you may not be able to reconnect to it via Remote Access after a reboot. DHCP automatically receives an IP address from the server whenever the px4-300r restarts. This is a very simple way to configure the px4-300r but can cause problems with your router's port forwarding settings. The router does not dynamically update port forwarding settings and cannot port forward to your px4-300r if its IP address changes.

To resolve this problem, try one of the following processes:

●Increase the length of the DHCP lease: Your router attempts to remember all DHCP clients and assigns them the same IP address every time they request an IP address; however, the router forgets clients if they do not request an IP address for a certain amount of time. Your router has a setting for the duration of the validity of the DHCP lease. If your network requires DHCP, this may be a good solution; however, it is not always guaranteed to work. Occasionally updating your router's port forwarding settings may be required.

●Use Static DHCP: Some routers allow you to assign Static IP addresses through the DHCP system based on the MAC address of the device. This ensures that the px4-300r always gets the same IP address, and your port forwarding settings are always correct. Static DHCP allows you to leave your px4-300r in DHCP mode. Refer to your router's documentation for more information on configuring DHCP settings.

●Use a Manual IP Address: Changing the Manual IP address reduces the reliance of your px4-300r on the DHCP server; however, you must perform additional configuration for it to work properly.

1.Log in to your router and write down the DHCP range it is using.

Troubleshooting Routers 143