If you use PPP as your connection to the Internet, client computers connected to a Software Base Station using Ethernet can be configured using the DHCP server on the Software Base Station computer.
Settings in the AirPort application on the Software Base Station computer
In the Network pane of the Software Base Station panel, select the checkbox for "Also support Ethernet client computers using NAT." This turns on DHCP services as well as NAT (Network Address Translation) and routing for the Ethernet connection.
Note: Versions of AirPort software earlier than 1.3 say "Also provide IP addresses on Ethernet" in the Network pane.
Settings in the TCP/IP Control Panel on the client computers
Select "Using DHCP Server" from the Configure pop-up menu. This instructs the client computer to obtain an IP address from the DHCP server on the Software Base Station computer.
Sharing an Ethernet Internet connection
If you use Ethernet as your connection to the Internet, client computers connected using Ethernet to a Software Base Station must be manually configured. The DHCP server on the Software Base Station cannot be used to provide an IP address to the client computers.
Settings in the AirPort application on the Software Base Station computer
In the Network pane of the Software Base Station panel, select the checkbox for "Also support Ethernet client computers using NAT." This only enables the routing service and NAT over Ethernet and does not provide DHCP services.
Note: Versions of AirPort software earlier than 1.3 say "Also provide IP addresses on Ethernet" in the Network pane.
Settings in the TCP/IP Control Panel on the client computers
2. Enter an IP address in the range of 10.0.2.51 to 10.0.2.254 in the IP Address field.
3. Enter 255.255.255.0 in the Subnet mask field.
4. Enter 10.0.2.1 in the Router address field.
5. Enter the IP address of the name server in the Name Server addr. field. This IP address is usually provided to you by your Internet service provider.
Software base station is not a feature of Mac OS X. For related information, see technical document 106507: "Mac OS X 10.1: AirPort Software Base Station Is Not an Included Feature"
Wireless Internet access requires an AirPort Card, AirPort Base Station, and an Internet service provider, for which fees may apply. Some ISPs are not compatible with AirPort. For more information, see technical document 106590: "AirPort: Requirements for Wireless Internet Access."