China's Ministry of Information Industry (MII) has warned that websites who do not comply with recent registration guidelines will have their Internet Protocol (IP) addresses blocked.

MII says about 30% of websites in China still have not registered for an Internet Content Provider (ICP) identification number. As a result, not only will these websites face closure, but they will also bring risks to others who share the same IP address with them.

About 80% of China's 660,000 domestic websites are built through renting a virtual host computer which is based on sharing the same IP address and servers. Once a particular Chinese user breaks the rules, many others who share the same IP address and server will be affected.

Net.cn, one of the largest Chinese domain name registration and virtual host computer provider, is now giving free IP addresses to special enterprises who register with them to help them avoid being affected by others.

However it is still unclear how MII will block those errant websites. One way is to distribute a list of IP addresses, similar to the DNS blocklists distributed by anti-spam groups like Spamhaus. Then Internet providers in China will use those lists to cancel requests to visit the banned websites. Another way to block access is to give the Internet Data Centers (IDC), themselves, the list of banned IPs and have the IDCs police access to their own servers.