The default IP address for AT&T routers is typically "192.168.1.254". However, it's important to note that the IP address can vary depending on the specific model and configuration of your AT&T router. If you are unsure of the IP address for your AT&T router, you can try the default address mentioned above or check the router's documentation or the label on the router itself for the correct IP address. Alternatively, you can access the command prompt on your computer and type "ipconfig" (for Windows) or "ifconfig" (for macOS/Linux) to view the default gateway IP address, which should be the IP address of your AT&T router.