Mac OS X Leopard: The Missing Manual

Broadband Connections

If your Mac is connected wirelessly or, um, wirefully to a cable modem, DSL, or office network, you're one of the lucky ones. You have a high-speed broadband connection to the Internet that's always available, always on. You never have to wait to dial, disconnect, or download. You're connected to the Net via your Mac's Ethernet jack or AirPort antenna, leaving the dial-up era behind.

Automatic Configuration

The real beauty of most broadband connections these days is that they require no setup whatsoever. Take a new Mac out of the box, plug in the Ethernet cable to your cable modem (or choose a wireless network from the menulet), and you can begin surfing the Web instantly.

That's because most cable modems, DSL boxes, and wireless base stations automatically feed all of the necessary configuration settings to the Mac (including techie specs like IP address and DNS Server addresses), courtesy of a glorious feature called DHCP.

UP TO SPEED: PPPoE and DSL

If you have DSL service, you may be directed create a PPPoE service. (You do that on the Network pane of System Preferences; click your Ethernet connection, and then choose Configuration→Create PPPoE Service.)

It stands for PPP over Ethernet, meaning that although your DSL "modem" is connected to your Ethernet port, you still have to make and break your Internet connections manually, as though you had a dial-up modem. ...