How to make sure your Network settings are ready for ADSL. This guide is made for Mac OS 10.6.
Open System Preferences and find Network.
When in Network, choose Ethernet in the connection list on the left. It should come up like the picture below, with numbers in IP Address, Subnet Mask and Router. The numbers should be something like xxx.xxx.xxx.xxx
Click on the button that says Advanced and you'll get this screen, choose the tab that says: TCP/IP.
Make sure Configure IPv4 is set to: Using DHCP. This will give your computer an IP address automatically.
In the DNS tab, the DNS IP should show up autmatically, and be grayed out. If you want to add a manual DNS, click on the + sign.
On the Proxies tab, make sure there is no tick in any of the options as your connection should find it automatically.