Reader Stuart Landay would like to combine wireless and wired networking. He writes:
Is it possible to hook up an Ethernet switch to an Apple Airport Extreme Base Station in order to connect more than one computer with an Ethernet cable? Will the router in the base station assign an IP address to each of the wired computers?
Sure, that’s one reason Apple included the Ethernet LAN port on the back of the base station. To get the full lowdown on how to set this up, I strongly suggest that you peruse Apple’s very helpful Designing AirPort Extreme Networks document.
For those averse to reading documentation, the short version goes like this:
String an Ethernet cable between your DSL or cable modem and the base station’s Ethernet (WAN) port. String yet another Ethernet cable between the base station’s Ethernet (LAN) port and one of the ports on the switch. String similarly between the switch and your wired computers.
Run the AirPort Setup Assistant (located in the Utilities folder) and see if the questions it asks and the answers you give provide relief.
If not, launch the AirPort Admin Utility (also located in the Utilities folder), select the base station, and click Continue. In the Internet tab tell the base station how you connect to the Internet — Connect Using Ethernet and then choose Using DHCP or Manually from the Configure pop-up menu. If you have an assigned IP address (and therefore need to configure manually) enter such necessary information as IP address, subnet mask, router address, and DNS servers into the appropriate fields.
The Network tab is where much of the magic happens. Enable the Distribute IP Addresses option and choose either Share a Single IP Address (Using DHCP and NAT) or Share a Range of IP Addresses (Using Only DHCP). If you choose the former, the base station will dynamically serve, by default, IP addresses within the 10.0.1.2 - 10.0.1.200 range (it can also serve 172.16.1.1 or 192.168.1.1 addresses). The latter option lets you define the specific range of IP addresses — 10.0.1.25 - 10.0.1.39, for example.
When you use the first option all you need to do on the computers attached to the switch is to open the Network system preference, choose Built-in Ethernet, click the TCP/IP tab, and choose Using DHCP from the Configure IPv4 pop-up menu. The computers will grab a dynamic IP address from the base station via the switch. With the latter option you’ll need to choose Manually from the Configure IPv4 menu and assign a specific address within the range you specified in the AirPort Admin Utility — 10.0.1.24, for instance. You’ll also want to enter 255.255.255.0 in the Subnet Mask field, 10.0.1.1 in the Router field, and the address(es) of your DNS servers.