Internet Engineering Task Force (IETF) just adds a new HTTP response code 451 on its standard to make it clear when the website is restricted for legal reasons. What different HTTP errors we usually saw on websites: 404 not found, 403 forbidden and more but when a court or government block a content on the internet, it’s hard to define why the content is not accessible.
Previously, I saw many sites showing response code 403 Forbidden in the censorship situation, but it didn’t mean the page was blocked due to legal reasons. The new error 451 message is the best way to clearly explain to visitors that the resource is restricted due to the government censorship.
The status code 451 was first proposed by Tim Bray in 2013 inspired by the Fahrenheit 451 novel, and IESG approved the code officially on 18 Dec, 2015. Here’s a public announcement by the chairman of IESG on Twitter.
— Mark Nottingham (@mnot) December 18, 2015
Mark Nottingham, the chairman of the IETF HTTP Working Group writes in a blog post why do we need 451.
As an example, you can take a web page is taken down due to copyright, privacy, laws, or any other law or court order. The above screenshot is a demo of HTTP message 451.