Block (Internet)

On the Internet, a block, or ban (also sometimes referred to as a banhammer) 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. Some countries, including China and Singapore, block access to certain news information. In the United States, the Children's Internet Protection Act requires schools receiving federal funded discount rates for Internet access to install software that blocks obscene content, pornography, and, where applicable, content "harmful to minors".

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 Wikimedia projects, 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 unrestrictedly block other users, typically by preventing them from sending messages or viewing the blocker's information or profile. Privileged users can apply blocks that affect the access of the undesirables to the entire website.

Blocking is used by moderators and administrators of social media and forums to deny access to users that have broken their rules and will likely do so again, in order to ensure a peaceful and orderly discussion place. Common reasons for blocking are spamming, trolling, and flaming. Some criticize cases of the use of bans by administrators of large websites, such as Twitter, saying that these bans may be politically or financially motivated. However, websites have a legal right to decide who is allowed to post, and users often respond by "voting with their feet" and going to a place where the administrators see their behavior as acceptable.