I am looking for a way to grant access to a secured WiFi network, based on certain external information?
For example, some server on the internet could store MAC addresses that ought to be granted access, in addition to MAC addresses stored in router itself.
Or, access to WiFi network is password protected, but it will be granted if password supplied by newly connected device matches one of the passwords contained in a dynamic list.
The idea behind this question is the following: I have WiFi with flat rate plan. I should not resell it, but I can share it with friends and family, when they pay me a visit.
Now, I would be willing to allow access to an unknown "visitor" which happens to be within the range, provided he does the same with his WiFi. If there are enough like-minded individuals within an area, I could get access to free internet at many more spots.
However, this should work automatically, should not incur any costs on new participant, and should end its participation X days after he ceases to provide free internet to others.
Are there any security concerns? I am aware that this is still somewhat a general question, and pointing me into the right direction how this could be achieved would be great help!