Try this link. I don't have this but located a link to tell you how.
Get details on using your BGW210 to connect to the internet and get help with common issues.
www.att.com
Robert
Thanks for sharing this Robert, this fixed my issue.
Attaching the steps from the link for future reference should the link stop working.
Set up port forwarding on AT&T Smart Home Arris BGW210-700
To open a port for user-defined applications:
Go to your gateway settings.
Select the Firewall tab.
Enter the Device Access Code found on the side of your gateway.
Select NAT/Gaming.
If you receive a warning message, visit the AT&T Port Forwarding tool to enable port forwarding on your account. Then, you can continue with the steps in this solution.
From the Service drop-down, select the application for port forwarding. If your application isn't in the list, or you are setting up port forwarding for a device:
Select Custom Services.
Enter the name for the application or device in Service Name.
Enter the port(s) you wish to open for Global Port Range.
It is recommended to create a separate service entry for each port as opposed to using a port range. In this case the port number should be the same in the Global Port Range fields.
In Base Host Port, enter the port number used for the first Global Port Range section.
Select the appropriate Protocol from the drop-down for the application or device you are adding.
Select Add. Repeat as needed for additional applications and devices.
When all applications or devices have been added, select Return to NAT/Gaming. Your new applications or devices will display in the Applications list.
From the Needed by Device drop-down, select the device name or IP address of the device to open the port.
Select Add.
When your selections display in Hosted Applications, select Save.
