The Banned IPs module is useful when you want to prevent users from some IP addresses to access the website. This happens typically when the user enters indecent posts into a forum or when she behaves in some other unwanted way. These bans can be set either for separate web sites or globally for all web sites in the system.
Page url: http://devnet.kentico.com/docs/devguide/index.html?banned_ips_module_overview.htm