IP filtering

The IP filtering is aimed at the IP addresses of those various resources on the Internet. It requires the user to know fully the knowledge of IP. Actually, the IP distribution has basically a global regulation, the general knowledge of it may be found out by the searching of Internet. The keyword for the search may be “IP address distribution”. The user may setup with these rules the blockage to those Web sites in a certain region to be banned. 
Some big Web sites such as yahoo, sina or so have more IP addresses of their own; therefore, to simply block one or two of their IP addresses will not be helpful.