On December 18, 2015, the Internet Engineering Steering Group (IESG) approved HTTP Status Code Error 451 “Unavailable For Legal Reasons”. This code is a more specific version of the existing 403 “Forbidden” code. The new 451 code is intended to be displayed when accessing a web page that is blocked by government or ISP. In other words, code 451 makes it clear that information has been censored, whether for national security, copyright, court order, or other legal reason.
Lest you think I’m reaching when I say “censored,” you should know that the number 451 is not arbitrary. The new HTTP Status Code is an homage to Ray Bradbury’s classic 1953 fictional political novel “Fahrenheit 451,” about a dystopian future where television “informs” the public and “firemen” burn outlawed books. It’s a classic story of oppressive government using censorship to control how people think. And while burning books might not be the ultimate form of government censorship in the modern world, the symbolism is well understood. Government suppression of information, whatever form it takes, should never be taken lightly.
Unfortunately, this new status code is optional, requiring web developers to adopt it. Because of this, the same agents responsible for censorship might also be able to avoid status code 451 from being displayed. If nothing else, at least we can applaud this attempt at transparency.