We forwarded port number and also set DMZ zone after AT&T UVerse installation but no luck.

AT&T will ask you to pay more in order for your camera to be accessible from outside. Sign up for Comcast, this feature is free from Comcast. 

I contacted AT&T ConnecTech Service rep. yesterday. The tech named "Daryl Fernandez" said UVerse customers must subscribe to an additional service which costs $15/ month in order to be able to gain access to cameras from outside the house. Here is the chat transcript:

[edited for privacy-please do not post personal or unique information such as but not limited to full names, employee ID numbers, email addresses, phone numbers, account numbers, etc.]

AT&T suggests ConnecTech, which is a paid service, to those who are not capable of making advanced configuration changes without assistance.

There are a gracious plenty of U-verse subscribers who have successfully hooked up and accessed security cameras without paying ConnecTech for assitance.

Those who have the wit to come to these forums and seek assistance rather than going to ConnecTech, and/or before switching to another provider can get assitance.

@joeackerman2, if you would provide screen shots of your configuration pages (please mask your actual public IP address if it appears in the screen shots) and we'll help you get this straightened.

Also, before we begin, let me be sure that:

• you've tested the cameras on the LAN using their LAN IP addresses and they work, but
• when you attempt to access them externally using your Public IP address and the port you've assigned for port forwarding, you can't access them.

When we had Comcast, it was easy, we just added IP of the camera in the DMZ zone list. 

Now in UVerse, we tried both ways. Setting the camera as a DMZ device and creating a custom device with the port number forwarded. Neither worked when we attempted externally. Accessing from local LAN ip (192.....) always worked though. Screenshots attached below:

https://drive.google.com/open?id=0B0McLC1Ts-qMd0Yyb0hYYzFlbk0

https://drive.google.com/open?id=0B0McLC1Ts-qMa3NKX08ySUdyVnc

https://drive.google.com/open?id=0B0McLC1Ts-qMRjNmU0lPZUlGRzg

Pictures didn't upload to the forum server. I have added links to my google drive.

I see one wierd thing: Shot 1 refers to your application name as "8080 PORT" and the device as "S4_CAM".  However, Shot 2 defines an application named "S4" (which isn't the same as 8080 PORT).

If you haven't already, try doing a factory reset on the Gateway, and re-do the setup.

I'm having trouble visualizing the question you're asking about.  Can you screenshot it?

Here is the screenshot : 

https://drive.google.com/open?id=0B0McLC1Ts-qMd0RnRUhxYnVDbmM

S4 is a user-defined application ( I couldn't find existing app which allows port 8080 through firewall).

I'm having the same issue. My coworker has Comcast and he showed me how easy it is to setup DMZ zone for individual ip cameras. I'm leaning towards switching my cable and internet to comcast.