How to Add Router to DSL Modem

Quick Method

#2 Below
change local ip of router to 192.168.2.1

(assuming dsl modem ip is 192.168.1.254)

DSL with Router Setup (Motorola 2210)
 
In order for a router to work properly, the WAN (internet), and LAN (home network) connection must be on two different networks. By default, the Motorola 2210 uses 192.168.1.254 as the default network, and gives a single IP address to a connect device, such as a laptop or PC. If you use a linksys router, it connects to the modem in the exact same way. This method of Automatic IP address assignment is called DHCP. By default, the WRT54G (and most routers) use this configuration for the WAN, or Internet, connection. In order for devices to connect to the router, they must be on a network that is different from that of the DSL modem. Changing the LAN, or home network side, of the router interface to 192.168.2.1, changes the network that it is on. The router now can forward packets between your home network and the Internet successfully.

-There is a difference with AT&T DSL and RR Cable Internet devices:

The main difference is Cable modems use the Automatic DHCP connection by default, and give a World-Wide IP address directly to the modem without authentication (RR uses one-time only MAC address registrations on a per modem basis). DSL modems, require a PPPoE connection. This Point-to-Point protocol requires a username and password before an IP address is given. If you connect to the DSL modem you will see that you are required to enter your username (name@sbcglobal.net) and password. Read below on different ways to configure this connection.

-There are multiple ways to setup this connection, here are a couple:

1.
Change the DSL modem to initiate the PPPoE connection on the Computer (by default it is set to modem).
To do this, connect the modem directly to your computer by ethernet cable, then  log into the DSL modem at 192.168.1.254 via your internet browser.
On the left side of the page, select "PPP Location".
It will probably ask for the modem access code, which should be on a sticker on the bottom of the modem.
Once in, set the modem to PPP is on the Router (if the third option of Bridge Mode is there, use that).
Then save the changes & let the modem reboot.
At this point, the modem is just a modem - it no longer holds the login info for your internet connection.
Changing this setting means that the PPPoE connection must now be configured on the Router.
You must now change the WRT54G router from "Dynamic - DHCP" to "PPPoE".
 
Now, re-connect the router to your modem & computers.
Go into the router settings (if linksys, input 192.168.1.1 (blank username, "admin" password)) and change "DHCP" to "PPPoE" and input your DSL Internet connection login info and save the changes in the router.
 
The password is your DSL Network Password and not your Member password! 
 
If you use this method you can leave your router set to 192.168.1.1.
Dont mess with any other settings in the router other than configuring different wireless settings.
 
Last step, turn off all devices (modem, router, computers). Now, boot them back up in this sequence: modem first (wait until DSL light goes solid green - don't worry about the other lights), then the router, and then the computers.

2. (fastest/easiest)
 Leave the DSL modem with the PPPoE connection at the modem (default). This means you must reconfigure the router to have a different IP address than 192.168.1.1 (as explained above).