Error 451 is the new Ray Bradbury-inspired HTTP code for online censorship
Error code 451 tells you when content you want to see is blocked due to "legal obstacles."
The web is full of cryptic status codes that your browser shows when it can’t connect to a website, such as 403 Forbidden or 404 Not Found. Now the Internet Engineering Steering Group is adding one more error code for your browser—but this time it will make it all too clear why you can’t see something.
The IESG recently approved status code 451 that tells visitors they can’t see the requested content due to “legal obstacles,” which usually means government censorship. Former Google engineer Tim Bray suggested code 451, inspired by Ray Bradbury’s dystopian novel Fahrenheit 451, back in 2012.
Status code 451 can be used by a website such as Facebook or Twitter, or by network intermediaries like a firewall or ISP. At first glance, 451 seems like a great idea to notify citizens in repressive countries if their government is blocking specific content. But those types of governments are also likely to prevent their citizens from even seeing that error code in the first place. Plus, if you live in a country where information is restricted you’re probably well aware of why you can’t see a certain site.
Democratic and semi-democratic countries are the more likely places where 451 will become useful. Take, for example, the U.K. government’s decision in 2012 to force ISPs to block torrent site The Pirate Bay. Instead of throwing up a 403 Forbidden code, ISPs could instead return 451 to make it clear why their customers can’t see specific content.
Why this matters: As the web becomes even more central to our lives there could be all kinds of reasons for a site to be blocked. Perhaps a court will order a webpage with a 3D printing schematic blocked because it violates a patent, trademark, or copyright. A government body may decide to block more torrent or streaming sites, or perhaps the “right to be forgotten” in Europe will be expanded to affect specific webpages. Whatever the reason, in any country where there’s at least some freedom its citizens must know when their governments have restricted their ability to access information. Error code 451 scratches that itch.