A fix, but not a pretty one!
I had the same problem. The wifi network appears on the iPhone, and it claims to be connected, but cannot be used as the iPhone doesn't get allocated a valid IP address on the network. I have an iPhone 4 and an extreme base station. After many resets and following suggestions on various forums, nothing worked.
It appears that the problem is that the Airport Extreme is failing to correctly allocate a private IP address to the iPhone using DHCP - an automated connection protocol. No idea why this isn't working, it ought to be straight forward - possibly a bug in the latest iPhone iOS?
The way I solved it was to use the Airport Utility to change the connection setting on the airport Extreme from automatic allocation of IP addresses, to only allocating a range of IP addresses from 2 to 200.
On the iPhone I then change from DHCP to Manual and set the IP address to xxx.xxx.xxx.201 (where the x's are the private IP address range chosen by Airport Utility). If needed, another device could be set to 202 etc.
All very ugly, sorry, but at least it works if nothing else does. Best of luck. I hope Apple finds out why it is happening and fixes it, it seems a lot of people are also struggling with this.
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I had the same problem. The wifi network appears on the iPhone, and it claims to be connected, but cannot be used as the iPhone doesn't get allocated a valid IP address on the network. I have an iPhone 4 and an extreme base station. After many resets and following suggestions on various forums, nothing worked.
It appears that the problem is that the Airport Extreme is failing to correctly allocate a private IP address to the iPhone using DHCP - an automated connection protocol. No idea why this isn't working, it ought to be straight forward - possibly a bug in the latest iPhone iOS?
The way I solved it was to use the Airport Utility to change the connection setting on the airport Extreme from automatic allocation of IP addresses, to only allocating a range of IP addresses from 2 to 200.
On the iPhone I then change from DHCP to Manual and set the IP address to xxx.xxx.xxx.201 (where the x's are the private IP address range chosen by Airport Utility). If needed, another device could be set to 202 etc.
All very ugly, sorry, but at least it works if nothing else does. Best of luck. I hope Apple finds out why it is happening and fixes it, it seems a lot of people are also struggling with this.