What If You Have to Share?
Macs can share a wireless internet (or network) connection among several computers. However, they can also establish local computer-to-computer networks that do not require an external network to function. These kinds of c-to-c networks might be used to share files or play a networked game.
Let's see how to set up the sharing process. First, we determine whether any other computers, aside from the one making the wireless connection with the base station, will be allowed to share the Internet connection going to the base station. This is done in the Sharing panel of System Preferences:
If wireless sharing is enabled, a dialog box shows up so that the physical parameters of the wireless network, along with security options, can be initialized.
Password protection of a wireless network is a basic security measure. It can be enabled or changed by using the Airport pane of the Airport Admin Utility. The following options then become available:
Not Enabled: Choosing this option turns off all password protection for the network. Any computer with a wireless adapter or card can join the network.
128-bit or 40-bit Wireless Equivalent Protection (WEP): Choose either of these options to protect your network with a WEP password. The Airport Extreme Base Station supports 40-bit and 128-bit encryption. Choose standard 40-bit encryption for maximum compatibility; or choose 128-bit encryption, which provides maximum WEP security. If you choose 128-bit encryption, only computers with 128-bit encryption-capable wireless networking cards can join your network. If you choose 40-bit encryption, computers with 40-bit and 128-bit encryption-capable wireless networking cards can join your wireless network, but they join with only 40-bit encryption.
WPA Personal: Choose this option and enter a password for the wireless network. When a wireless client enters the password correctly, the base station starts the encryption process. The password you choose can be between 8 and 63 ASCII characters; if you choose to enter a Pre-Shared Key, it must be exactly 64 hexadecimal characters.
WPA Enterprise: Choose this option if you are setting up a network that includes a RADIUS server for the 802.1X flavor of networking previously mentioned. Enter the IP address and port number for the RADIUS server, and enter the password for the server.
WPA security features are available only to Airport Extreme Base Stations, Airport Express, Airport and Airport Extreme clients using Mac OS X 10.3 or later and Airport 3.3 or later, and clients using other 802.11 wireless adapters that support WPA.
Configuring the client computer depends on the exact way that it is connected to the WLAN (not discussed in this article). Apple publishes a document called "Designing Airport Networks" that is recommended for those who want an explanation of all the possible variants.
Non-Apple base stations (also called APs for Access Points) can be used in Macintosh WLANs. The exact setup procedures vary with the AP and should be provided (as well as any needed software) with your hardware. The 802.11 physical layer protocols allow mixing and matching of hardware manufacturers as long as they follow the protocol's rules. It's good to remember, though, that some Apple software (which is written specifically for Apple hardware) may not work with anything but Apple hardware