Your Motorola wireless modem is a gateway device that serves multiple roles in your home network. Its primary function is to modulate a cable Internet signal to receive the Internet address rules and configurations assigned from a service provider. Additionally, the Motorola doubles as a router by providing you with a local network address. This is why all network and port-related management tasks must be performed through its Web-based interface. If you are having errors relating to NAT on any of its connected devices, you need to forward any ports they use to their local IP. Access the gateway's port options from within your Web browser.
Open a Web browser. Type "192.168.100.1" in the address bar and press "Enter." This opens a Network Password dialog.
Type "admin" in the User Name box and type "Motorola" in the Password field, then click "OK." Both fields are case sensitive. This opens the Motorola configuration interface.
Click the "Gateway" link on the left pane, and then click the "Port Forwarding" tab at the top. This lists any current rules in the Configured Port Forwarding table.
Add a new rule by clicking the "Config" button. This displays the Add New Port Forwarding Entry section. Type a name for your rule in the Name field.
Type the starting port number in the Port Start field and the ending port in the Port End field. If you only need to open one port, type the same port number in both fields. If you need to forward multiple ports, you need to create a new rule for each port.
Type the local IP address of the device you want this rule to apply to in the LAN IP Address field, and then click in the selection box next to "Enable."
Click the "Add" button, and then click "Apply."