Access to Wifi after checking for user over internet

[Skippic]

I would like to know if there is a possible solution to:

A) usnig your computer to accept and refuse users trying to connect to your wifi router after consulting an internet server (your computer should check if this person is allowed or not, and based on that give or refuse the permission to connect, or possibly let everybody access, but kick afterwards all users without permission). Example:
1.) somebody tries to connect to your WiFi network
2.) your PC, after identifying this person (his mac address or whatever) searches in a database (internet or local)
3.) accepts or refuses his connection (kicks him from router)

For option A) I would like to know if any computer with administrator priviledges to the router can tell it who can be accepted and who not.

B) same scenario withought the PC (is there a possibility with todays standard routers to leave the decision making of accepting a user to a predefined internet server?)

For both situations, would the client need a special program?

And one last question, can the options A or B used to give the client a possibility to identify himself by letting him access only one predefined web page?

I understand similar solutions are in the payed WiFi spots.

Just to make sure I don't get unwanted replies: I know the possibility of making your WiFi accessible with a key and also the possibility of staticaly predefining a set of MAC addresses that can be accepted.

Thanks for reading ;)

[cszeto]

Since this appears to be in support of a business network, you might try http://www.enterpriseitplanet.com. They also have a forum too and it is geared at business networks.

This is pretty much beyond the scope of most SOHO networks, so there may not be too many responses to this subject across these forums.