Ok, this is just a regular blog post I wanted to help out others with this att setup, but it's nothing to do with cs-education.
ATT is offering $20/mo DSL in my area, and it seems like a great deal. It goes up to some terrible price in one year, so you have to remember to call them. Seems shabby to count on the customers forgetting to call and reset the rate, but for $20 I'm in, so I guess they have me figured out.
I don't mind that they have the super no-brainer install script to run things, but it's crazy that they don't ALSO have just include the few needed factual details for the tech savy. Not only are there no instructions included, but what's on their help boards is incorrect, so here is the right answer. I'm assuming you want to connect their modem to some networking gear, like a router or whatever:
1. Make a hardwire connection to the modem. Connect to 192.168.1.254 and change PPP to bridged
2. Now on your router, the att instructions tell you to enter your att username and password for the ppoe login. This is incorrect on my setup (I'm guessing it was correct at some time in the past). Instead, there is a special "network" password which you are not told, and this is what ppoe wants. Seems like this password would have been good to print on the data sheet that comes with the install. You can go to the following url, and use it to get a new auto-generated network password. Then type that in as the password for ppoe.
I suspect att would have been better off just leaving the ppoe without any authentication, instead solving it with a little logic at their end. Just looking at the help forums ... a vast amount of user and support time has been wasted on this, in contrast to the elegantly hard to screw up "I'm on my telephone line so I'm me" authentication scheme.