The Internet Engineering Task Force (IETF) has approved the use of the 451 HTTP status code for websites that are inaccessible for legal reasons such as government censored content or blocked copyrighted material. There are limitations as to whether internet users in different geographical regions will see this error code but the approval of 451 is an acknowledgement of the prevailing issues of internet censorship and online piracy.
Internet censorship image from Shutterstock
Most of us who have used the internet long enough would be familiar with the HTTP 404 (File Not Found) and 403 Forbidden error messages when we're unable to access a website. The HTTP 451 code has official joined the family of error messages with the IETF, an organisation which sets and promotes the adoption of voluntary internet standards, approving the use of it.
The 451 Code is a tribute to the seminal Ray Bradbury novel Fahrenheit 451 that most people interpret as a warning against state-based censorship (although the author has denied this as a major theme in his book). It has been in the works for several years but has finally been accepted. Now, note that I mentioned that IETF standards are voluntary and whether or not the HTTP 451 error code becomes mainstream will be dependent on whether it gains traction with technology vendors and governments.
Here's what Mark Nottingham, who chairs the IETF HTTP Working Group, has to say:
By its nature, you can't guarantee that all attempts to censor content will be conveniently labeled by the censor. Although 451 can be used both by network-based intermediaries (e.g., in a firewall) as well as on the origin Web server, I suspect it's going to be used far more in the latter case, as Web sites like Github, Twitter, Facebook and Google are forced to censor content against their will in certain jurisdictions. … In some jurisdictions, I suspect that censorious governments will disallow the use of 451, to hide what they're doing. We can't stop that (of course), but if your government does that, it sends a strong message to you as a citizen about what their intent is. That's worth knowing about, I think.
As mentioned, the error code can also be used to display websites that have been blocked due to violation of copyright such as torrent portals like Pirate Bay.
Sure, cynics could say the HTTP 451 error code is useless given that it's voluntary and doesn't actively do anything to fight for net neutrality, but it is step towards providing internet users with transparency as to why certain online content has been blocked.
Nottingham also noted:
[I]t gives a way to build systems to track censorship, and we've already seen discussions about leveraging 451 to prompt the user to try accessing the content in a different way.
[Via mnot's blog]