back to article New HTTP error code 451 to signal censorship

After a three-year campaign, the IETF has cleared the way for a new HTTP status code to reflect online censorship. The new code – 451 – is in honor of Ray Bradbury's classic novel Fahrenheit 451 in which books are banned and any found are burned. The idea is that rather than a web server, proxy or some other system returning …

  1. Crazy Operations Guy

    "451 degrees Fahrenheit being the auto-ignition temperature for paper"

    No, that would be 451 degrees Celsius, 451 degrees Fahrenheit would just make the paper fairly warm. The source Ray Bradbury called confused the two units and the mistake wasn't caught until well after publication.

    1. Anonymous Coward
      Anonymous Coward

      Re: "451 degrees Fahrenheit being the auto-ignition temperature for paper"

      Does Paper Really Burn at 451 Degrees Fahrenheit?

      Several Internet contrarians claim that Bradbury confused Celsius and Fahrenheit, putting his estimate off by 391 Fahrenheit degrees. They cite as evidence the Handbook of Physical Testing of Paper, which lists paper’s ignition temperature as 450 degrees Celsius. (Wikipedia cites the same source.) It’s not entirely clear how this number was arrived at, but it is an extreme outlier. The author appears to have used paper made with rayon or cotton, which could have a different auto-ignition temperature from pure wood pulp paper, but 450 degrees Celsius still sounds wrong. It’s also possible that the experimenters didn’t wait long enough or that they (and not Bradbury) switched Celsius and Fahrenheit.

    2. Blofeld's Cat Silver badge
      Headmaster

      Re: "451 degrees Fahrenheit being the auto-ignition temperature for paper"

      It appears that the Centigrade / Fahrenheit being swapped story is not true, although most experts set the figure at around the 470 - 480 F mark, depending on the type of paper and environmental factors.

      451 C is about the auto-ignition temperature for metals like magnesium.

      1. John Brown (no body) Silver badge

        Re: "451 degrees Fahrenheit being the auto-ignition temperature for paper"

        "451 C is about the auto-ignition temperature for metals like magnesium."

        Ah, so Bradbury was pre-imagining the Sinclair ZX Printer paper rolls?

    3. MacroRodent Silver badge
      Flame

      Re: "451 degrees Fahrenheit being the auto-ignition temperature for paper"

      This detail does not really matter. The number 451 has become iconic, the same way as 1984 and 666 are.

      1. Peter2 Silver badge

        Re: "451 degrees Fahrenheit being the auto-ignition temperature for paper"

        1984 would have been a better error code than 451. I think it would have differentiated it quite nicely from a technical error!

        1. MyffyW Silver badge

          Re: "451 degrees Fahrenheit being the auto-ignition temperature for paper"

          The BigBrother monitoring software used port 1984, which tickled me.

          Personally hoping for widespread adoption of 451 code in 2016 followed by a push in 2017 to challenge each instance that causes it to pop up. But perhaps I'm getting optimistic in my dotage.

  2. Crazy Operations Guy

    IETF were not persuaded is was a good use of a limited number of status codes

    Yeah and "418 - I'm a Teapot" was such a great use... Besides, would this already be covered under a couple other codes? Error 403 springs to mind or even 410.

    But that ignores the fact that most censorship is going to happen on the wire anyway, so either error 404 or a connection timeout would result. For most currently censored things, the protocol seems to be to use a redirect to a page describing why and who is censoring the data, something much more helpful than a cryptic error code.

    1. Blofeld's Cat Silver badge

      Re: IETF were not persuaded is was a good use of a limited number of status codes

      I was under the impression that the 451 reply code was to allow an automated response by the browser, in the same way that the 30X redirection codes are used.

      1. Destroy All Monsters Silver badge
        Paris Hilton

        Re: IETF were not persuaded is was a good use of a limited number of status codes

        But what the browser do? Automatically write a nastygram to congresscritters?

        1. Christian Berger

          Re: IETF were not persuaded is was a good use of a limited number of status codes

          "But what the browser do? "

          Route the request via a different route.

          1. P. Lee

            Re: IETF were not persuaded is was a good use of a limited number of status codes

            >>"But what the browser do? "

            >Route the request via a different route.

            In Mozilla's case, auto-redirect to TOR.

          2. Crazy Operations Guy

            Re: IETF were not persuaded is was a good use of a limited number of status codes

            Then "Error 305 - Use Proxy" would be the right response.

        2. Suricou Raven

          Re: IETF were not persuaded is was a good use of a limited number of status codes

          "But what the browser do?"

          Automatically attempt to fetch the file from google cache, archive.org, via Tor, and using an alternate DNS server. Or, if the query is an IMS, mark the version in the cache as 'does not expire, ever, do not IMS.'

        3. Rich 11 Silver badge

          Re: IETF were not persuaded is was a good use of a limited number of status codes

          But what would the browser do?

          Start to recite Moby Dick.

          1. Dodgy Geezer Silver badge

            Re: IETF were not persuaded is was a good use of a limited number of status codes

            ...But what would the browser do?

            Start to recite Moby Dick....

            "...Call me FireFox..."

        4. Anonymous Coward
          Anonymous Coward

          Re: IETF were not persuaded is was a good use of a limited number of status codes

          The point of not returning an existing code is that some Web 2.0 sites, such as Wikipedia, have been edited to remove "dead" links that weren't dead at all, just censored in the editor's location. 451 means Wikipedia et al. can have a policy regarding when to leave such links in place.

      2. veti Silver badge

        Re: IETF were not persuaded is was a good use of a limited number of status codes

        An automated response by the browser - sure, but only when the server or ISP tells it "Error 451".

        So basically, it's just relaying a message from the web server (or, just possibly, from one of the ISPs sitting between you and the website owner). As such, it's basically a political message, and about as meaningful as any other political message you can derive from a website.

    2. Anonymous Coward
      Anonymous Coward

      Re: IETF were not persuaded is was a good use of a limited number of status codes

      Clearly the IETF had the IoT in mind back in 1998 when they created HTTP 418.

    3. Voland's right hand Silver badge

      Re: IETF were not persuaded is was a good use of a limited number of status codes

      Yeah and "418 - I'm a Teapot" was such a great use

      I have used it in a commercial product prototype for the rest interface as a generic error code which means "I have no clue what I should do" (a fairly common situation in a provisioning system - modeling failures, unspecified comms failures across a gateway interface).

      The fact that it is not used in browsers is not an indication that it is not used.

      1. Old Handle

        Re: IETF were not persuaded is was a good use of a limited number of status codes

        I figure that outside of the original use in the coffee pot protocol, 418 is pretty much the server equivalent of this.

    4. Hairy Airey

      Re: IETF were not persuaded is was a good use of a limited number of status codes

      You do realise that 418 was an April Fool's Joke don't you? https://www.ietf.org/rfc/rfc2324.txt

  3. Triboolean
    Coat

    Cant resist:

    420: Server is stoned

    1. Anonymous C0ward

      419: Scam or phishing site

      1. Adam 1

        > 419: Scam or phishing site

        Why implement that in the HTTP? Doesn't rfc3514 already cater for this at the TCP layer?

    2. Christoph

      61613: Mail rejected as Spam

      (61613 Dec = F0AD Hex)

  4. phil dude
    Coat

    maths...

    314:who ate all the pi?

    P.

    1. This post has been deleted by its author

  5. komodo dragon

    So, every other post on Facebook is going to get a 415 error now?

    1. Old Used Programmer Silver badge

      Only if the author is from San Francisco.

  6. elDog

    And we all know what really happens. Status 200 - All'swell

    But the page you receive has been doctored to insert squirmy little thing, as well as some nice nude pictures to keep you occupied while the little thing does its work.

  7. David Roberts

    Already in use?

    Wonkypaedia suggests that this status code is already used by Microsoft.

    "451 Redirect (Microsoft)

    Used in Exchange ActiveSync if there either is a more efficient server to use or the server cannot access the users' mailbox.[68]

    The client is supposed to re-run the HTTP Autodiscovery protocol to find a better suited server.[69]"

    So interesting times if this part of Exchange is ever exposed to web crawlers.

    1. Charlie Clark Silver badge

      Re: Already in use?

      Fuckwits shouldn't be adding their own codes in IETF space.

  8. Someone Else Silver badge
    Thumb Up

    The new code – 451 – is in honor of Ray Bradbury's classic novel Fahrenheit 451 in which books are banned and any found are burned.

    I love it!

    Who says the IETF doesn't have a sense of humor?

  9. Anonymous Coward
    Anonymous Coward

    Can we also have error 551 to indicate 'Censorship needed'

    To be used by any server that is serving up goat.se or donkey porn (ass porn is usually fine), or sleb news or Twitter pages or Facebook or the mail online, or any Christmas ad ('go argosssss' - I mean, wtf is wrong with her?), any Apple ad since that Super Bowl one, or any 'get the facts' campaigns, or bloody runway expansion, or '10 weird old tips you didn't know about...', or pages of manufactured and pointless outrage, or whinging blogs written by self-centred egocentric immature morons who SHOULD GROW UP NOW, anything mentioning 'the cloud', or anything connected at all, no matter how obliquely, with Microsoft. That should do it.

    1. Lamont Cranston

      Re: Can we also have error 551 to indicate 'Censorship needed'

      You'll miss the internet when it's gone.

      1. Charlie Clark Silver badge

        Re: Can we also have error 551 to indicate 'Censorship needed'

        You'll miss the internet when it's gone.

        What? You mean apart from the porn? ;-)

        Just imagine going back to getting things done!

  10. Efros

    Call Karras

    666: Captain Howdy in residence.

  11. Anonymous Coward
    Anonymous Coward

    Shirley

    Code 451 indicates that the client has erred. The server error should start with a 5.

    1. Allan George Dyer Silver badge

      Re: Shirley

      No Winston, you have failed to control your mind.

    2. Ben Tasker Silver badge

      Re: Shirley

      Not necessarily, the client may have erred by being geographically located somewhere the content is censored.

      But, actually, it's not a server error anyway. The client has erred by either requesting content that isn't available (404) or content the client isn't authorised to request (403).

      The 5xx range is for where an action the server needs to complete has failed (upstream unreachable, parse error on a cgi script etc).

      4xx is definitely the right range for this use, though it's applicability does seem a little limited. You'd use it if you've received a takedown, but an on the wire censorship mechanism is unlikely to use it

  12. Anonymous Coward
    Anonymous Coward

    Living as we do, in a metric era, shouldnt that be :-

    HTTP Status Code 232.7777777777778

    The big question is, with “call me Dave” back-tracking on the FOI act, will ALL government websites return this error by default??

  13. A K Stiles
    Boffin

    An actual use for it...

    I could see using this in Academic circles, more precisely in Open Access Research Repositories where an article can't be publicly shared (possibly for a set time period) due to a publisher-imposed restriction. Then the research aggregation systems would discover why the item they are requesting is not available (possibly with a 'try-again yyyy-mm-dd' message in the description), rather than a generic forbidden message or a 200 response with a human readable page explaining that the item is not available.

    1. Ben Tasker Silver badge

      Re: An actual use for it...

      Including a tryagain date in the status code isn't the best way of doing it, status code descriptions should be (relatively) static.

      But adding a x-will-be-available-at or the like would be a nice touch, especially if people stick to the same header (much the same way as x-forwarded-for became defacto).

      It could also be nice, for dmca type takedowns, to have a "standard" x-see-more containing a link to chilling effects or similar

  14. Tom 7 Silver badge

    I'm sorry Dave

    I do feel this will trigger immediate attempts to get round the censorship.

    I may have to write a client side app to automatically forward this to your hacker of choice.

  15. Bill Michaelson
    Joke

    Still unclear

    How do we distinguish between "Censored: we don't want you to see this page" (451) and "Really Censored: we don't want you to know this page exists" (4??).

  16. Cuddles Silver badge

    Quis censores ipsos censor?

    "Don't expect to see 451 codes pop up in countries that routinely censor the internet, however. Typically those countries are not overly keen on letting their citizens know just how much information they are hiding from them."

    So what will be the new code to let us know the error code has been censored? And then the one to say that the censorship of the censor code has itself been censored. Who censors the censors?

    1. Cem Ayin

      Re: Quis censores ipsos censor?

      You certainly must mean "quis censebit ipsos censores" (or, if there is only one censor to watch, "ipsum censorem"), though this would still be dubious from a semantic point of view, since, while "censor" is certainly ethymologically related to "censere", the basic meaning of the verb is more along the lines of "to think (right)", "to believe" etc., as in "ceterum censo internautam non esse super grammaticos" and I'm not sure if "censorem censere" makes any sense at all (I don't have a copy of OLD at hand right now) but anyway this is now starting to get OT...

      1. Anonymous C0ward

        Re: Quis censores ipsos censor?

        Romanes eunt domus!

  17. allthecoolshortnamesweretaken

    The broser could redirect to a site that plays the internet censorship theme song.

    http://www.theregister.co.uk/2015/02/12/china_internet_censorship_theme_song/

  18. Amorous Cowherder
    Facepalm

    Oh yes, ISPs blocking Pirate Bay and many other torrent indexers, that only takes the addition of the a five letter word beginning with "P" to be suffixed in the website search and you're back on your merry way to "warez" nirvana.

  19. Marco Fontani

    418: Go away, I'm a teapot - http://tools.ietf.org/html/rfc2324

  20. Anonymous Coward
    Anonymous Coward

    clever, but the self enforcement aspect makes it sound a bit like the evil bit - https://www.ietf.org/rfc/rfc3514.txt

  21. hayzoos

    Applies to multinational conglomerate entertainment companies too, right?

    Say you are trying to stream latest online release from Disney studios while in Iceland. But, Iceland is not scheduled to receive it for another six months. It sounds like a legal reason for the content to be blocked and the 451 error would seem to apply. Then you know to use appropriate VPN to stream desired entertainment.

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