ModemWall

ModemWall is a dialing number filtering system for Windows 2000/XP(or later) operating systems. It is an agent designed to combat with unauthorized dialers( mostly known as porn dialers). ModemWall cuts off the problems caused by these dialers at the source : Prevent unauthorized numbers from being dialed regardless of the dialer which/who is trying to dial.
With ModemWall, users can specify Authorized/Unauthorized numbers logically by using easy firewall like rules. This feature makes ModemWall to be able to stop evil dialing parties whether they are known or unknown.