One of the easiest and best ways to share an Internet account is to use AirPort. In fact, using AirPort automatically means that you are able to share an Internet account among computers using an AirPort-compatible, wireless connection. And you can also use an AirPort-equipped Mac to share an Internet connection with machines on an Ethernet network.
When you install and configure an AirPort Hardware Access Point (also known as an AirPort Base Station), you can share the Internet account with which it is configured among AirPort-equipped Macs that can access that network. You can also share an Internet account among computers that are connected to the Hardware Access Point via Ethernet. This is because the Hardware Access Point is capable of acting as a DHCP server for the network and can provide that service to computers connected via AirPort and via Ethernet at the same time.
When used with a broadband connection, an AirPort Hardware Access Point also provides your network with some rudimentary firewall protection when you use Network Address Translation, or NAT (which will be explained later in the chapter). Because the only thing directly connected to the Internet is the Base Station itself, hackers can't see the computers that are connecting to the Net through the Base Station. They can see the Base Station, but because it isn't a computer, there isn't much that they can do to it.
Because AirPort is easy to install, configure, and maintain and because you also get wireless access for AirPort-equipped devices, using AirPort is one of the best ways to share an Internet account.
To learn how to install, configure, and use an AirPort network to share an Internet connection, see Chapter 11, "Using an AirPort Network to Connect to the Internet," p. 265.
An AirPort Base Station is a great way to share a dial-up Internet connection. Because the modem (if you use a dial-up account) and software required to maintain the dial-up connection are part of the Base Station, this method doesn't place any processing burden on the Macs that are using the AirPort network.