On the Internet, a block or ban is a technical measure intended to restrict access to information or resources. Blocking and its inverse, unblocking, may be implemented by the owners of computers using software.
Blocking may also refer to denying access to a web server based on the IP address of the client machine. In certain websites, including social networks such as Facebook or editable databases like wikis, users can apply blocks (based in either IP number or account) on other users deemed undesirable to prevent them from performing certain actions. Blocks of this kind may occur for several reasons and produce different effects: in social networks, users can block other users without restriction, typically by preventing them from sending messages or viewing the blocker's information or profile. Administrators, moderators or other privileged users can apply blocks that affect the access of the undesirable users to the entire website.