My internet blocked the forums but not the homepage...

You need to give AT&T some stick and have them fix the issue.

I have U-Verse and everything works fine for me. Try rebooting your router?

Have you reset the router? You might want to look at the back of the box for the admin password and IP address and do so.

Also good to connect to the wifi on your phone and see if it's giving you different IPs whenever you reconnect. (A sign it needs a reset)

I usually go on the 24/7 live chat support (you need a copy of a bill to verify yourself), and get issues sorted out there. They can do a quick connection test on their end and see if you need to have someone come out to fix your setup or replace the router.

I recommend the VPN service ProXPN to get a data point on what's happening. Their free service will allow you to see if the ISP is monkeying with the MR traffic. All of your traffic will be opaque to your ISP.

IMO, you can trust ProXPN. Steve Gibson has reviewed on Episode 400 of his Security Now! podcast (transcript here). I use their free service to get around some obnoxious ISP filtering (hello Panera Bread) and may subscribe to their pro service someday.

Note: it is possible that the ISPs could block VPNs. I haven't ever seen it happen, but it may some day.