Xbox Live and DSL

Not sure if this is the right place to post this, but here it goes. I am trying to connect my Xbox to Xbox Live. I have AT&T Yahoo! with a generic modem. Before I switched to Dish w'AT&T I used Comcast and worked perfectly fine. Whenever I connect now, the connection does not even pass the first stage, even though everything is connected. Any help?

I have used AT&T at my house and I have one question. Are you plugging your xbox directly into your modem or are you running it via Wireless. If you're running it through wireless, make sure you're not password protected, but that is plan and simple because it will prompt you to put in the code. Though, If you're running it directly through the modem, you'll have to do something special.

Go to System settings>Configure Network>Tab over to Additional Settings and click on PPPoE Settings.

Now you will need to type in the primary email address and password into your PPPoE settings so you can run through your internet as a user. So EX would be User name: DBAG@sbcglobal.net, Password: blahblah, Service Tag: SBC YAHOO. When I say primary, I mean who bought and is paying for the service, you can add several email accounts to the primary. When I lived at home, my mother's was primary so I had to use her information. I hope this helps you.