First, this is really easy to set up and since its U-Verse you already have a static IP address that comes with the U-Verse router/server.
1) Step one, Get your external network IP address. just type http://www.myipaddress.com/ in your browser and you get that.
2) You need to open the firewall for just the app you want. Any app you make available will be just a port on the external IP address. As an example my application which is on the default port 80 of an internal local server is set up as port 8091 of my external IP so I reach it with http://18.104.22.168:8091
a) Go to U-Verse control panel by typing http://192.168.1.254 in you browser
b) In the top tabs select “settings”
c) Under settings select tap for “Firewall”
d) Select the top bar option of “Applications, Pinholes and DMZ”. You should see select a computer as step 1 and edit firewall as step 2. We are going to the step 2 first.
e) Near the bottom of page click “Add a new user-defined application”
f) This part is really strait forward –
i) give it a simple application name
ii) keep protocol on TCP
iii) Port range should is just the port where the application delivers the content in you local network. In a normal web server that’s 80 so the values for both is the number 80.
iv) Leave timeout empty
v) Map to host Port is just whatever you want it to be but remember that is the port your external access is going to be using, I used 8091.
vi) leave the application type blank.
vii) hit add to list
vii) select the back button. You should now be back at the select a computer page.
g) Select you internal server by name or type it’s IP if you have a static on setup
h) down below select “Allow individual applications”
g) back at the edit firewall you can now see your new application in the list. Just move it over to hosted applications using add and your done.
OK that’s it you should now be able to test it using something from outside you local wifi network.