I get this message on macbook air now and I am also using my iphone through my airport router.... how do I get my macbook back working on my router network?
Your router assigns IP addresses in sequential order.
There are three solutions.
1. Always turn your devices on in the same order so they get the same IP address.
2. Set up the router to assign IP addresses using DHCP reservations based on the MAC address of the device.
3. Get a router that automatically assigns IP addresses based on the device's MAC address.