Apple iMac (Early 2009) - Manual (Page 46)

46 Chapter 4 Problem, Meet Solution
If you have two or more computers sharing an Internet connection, be sure that your
network is set up properly. You need to know whether your ISP provides only one IP
address or multiple IP addresses, one for each computer.
If only one IP address is provided, then you must have a router capable of sharing the
connection, also known as network address translation (NAT) or “IP masquerading.”
For setup information, check the documentation provided with your router or ask
the person who set up your network. The AirPort Base Station can be used to share
one IP address among multiple computers. For information about using an AirPort
Base Station, check Mac Help or visit the AirPort Extreme website at
www.apple.com/support/airport.
If you can’t resolve the issue using these steps, contact your ISP or network
administrator.
Problems with AirPort Extreme Wireless Communication
If you have trouble using AirPort Extreme wireless communication
 Make sure the computer or network you are trying to connect to is running and has a
wireless access point.
 Make sure you have properly configured the software according to the instructions
that came with your base station or access point.
 Make sure you are within antenna range of the other computer or the network’s
access point. Nearby electronic devices or metal structures can interfere with wireless
communication and reduce this range. Repositioning or rotating the computer might
improve reception.