If IIS7 does not listen the incoming connections trying to be made to a particular IP address,
even if the binding is set up correctly, check the output of the following command:
netsh http show iplisten
The IP address must be in the list to respond the requests.
To add an IP, type in the following command:
netsh http add iplisten x.x.x.x
It seems, that data is stored in the registry:
See http://support.microsoft.com/kb/954874 for more detail.