So I got a letter in the mail a while back saying my neighborhood is being migrated to AT&T U-Verse and there would be new equipment required and faster speeds...
Well, I didn't like the sound of "new equipment" so I googled what kind of equipment I might get. What I ended up with is this: AT&T Motorola NVG510. As you can see, there is no official page for this modem. No official manual, specifications, help guide, anything. The only semblance of documentation is this draft copy of the manual sent for FCC testing.
There are numerous limitations and other problems as well.
You can't set which DNS servers gets handed out by dhcp (must use AT&T's buggy servers )
No UPnP support. Not a problem unless you know, doing router bridging is non-trivial
See above about router bridging being way more difficult than it should be
Extremely frequent line drops. I had a total of one time of my internet going out with regular DSL over nearly 2 years. Since getting U-Verse, my connection drops multiple times per day.
I finally got the modem to do "bridge" mode and forward to my OpenBSD router. Yet another problem I found with the modem is it gives out the wrong subnet mask for it's public IP DHCP server. It handed out 255.255.255.255 when my fixed IP was X.X.X.80 and the gateway IP was X.X.X.1. It obviously needed to be 255.255.255.0
If cable internet was available in my town, I would have switched to it by now.