Access your AT&T modem to make detailed settings to its configuration. To access your modem, first enter the modem's IP address into your Internet browser's address bar to be taken to its configuration screen. The modem's IP address is usually located on the bottom of the device. It will appear as a series of numbers, such as "192.168.1.254." The IP address you enter depends on the type of modem you own, since they vary by manufacturer. Access your AT&T modem's settings in less than five minutes.
Log onto the Internet by double-clicking the browser icon located on your desktop. Alternatively, go to "Start" and "All Programs," then click on the name of your Internet browser application from the list that appears.
Locate your modem's IP address and enter it into your browser's address bar. Turn your modem over and copy the number on the IP address sticker into your address bar using your computer keyboard. Enter "192.168.1.254" for Motorola modems, "192.168.1.254" for 2Wire, "192.168.1.254 for Westell, "192.168.1.1" for Linksys, "192.168.2.1" for Belkin, "192.168.1.1" or "192.168.0.1" for Netgear, and "192.168.100.254" or "192.168.0.1" for D-Link.
Enter the modem's username and password, or device access code, into the appropriate fields on the next screen. Select "Advanced" if prompted on the next screen. The AT&T modem setting screen will now appear on your screen.