Abstract: Protecting open Web sites from known malicious users in a World Wide Web (Web) communication network with access to a plurality of open Web sites responsive to requests from users at IP addresses throughout the Web. There is provided in association with a protected open Web site, a stored list of the IP addresses of known malicious users combined with means for comparing the IP addresses of each user requesting access to the protected open Web site to said list of IP addresses of the known malicious users. There are also implementations responsive to the comparing means for diverting to an alias address for the protected Web site any request from the IP address of a malicious user. The alias address is provided by a function associated with the protected open Web site. The present invention is applicable in circumstances where the malicious users or “crackers” are already known.