Stack Exchange has removed a post (cached version) due to a DMCA takedown notice, but the response code is 404, indicating the resource could not be found. That is incorrect. I am wondering what it would take to implement the display of the proper response code of 451 instead of 404.

A 451 response indicates that the server is denying access to the resource in response to a legal demand (source).

  • 4
    Agreed completely.
    – Undo
    Apr 20, 2013 at 3:42
  • 11
    Has this status code actually been approved yet? All I can find on Google is that it was proposed. Generally you don't implement things that aren't standards yet.
    – animuson StaffMod
    Apr 20, 2013 at 3:52
  • 7
    If we waited until things became a standard before using them, we wouldn't be using HTML5 at all. This proposal has a lot of momentum and support behind it, so I don't see this proposal falling by the wayside.
    – L0j1k
    Apr 20, 2013 at 4:03
  • 2
    Most definitely not approved yet. It's only a draft, and should therefore not be used. Apr 20, 2013 at 4:07
  • 9
    Like all of HTML5.
    – L0j1k
    Apr 20, 2013 at 4:13
  • 1
    And what if it does fall through? Or what if the status code ends up being 452 when it gets approved? Everyone is just supposed to go and change everything? It's better to just wait for the official specification, especially since as far as I can tell no browsers even look at this status code, so it'd essentially be a useless number being sent to the client.
    – animuson StaffMod
    Apr 20, 2013 at 4:25
  • 3
    What would we do if something from HTML5 falls through? Also, clients look at whatever custom error page SE decides to put up for its respective response code. Putting a 451: DMCA (or NSL) instead of a 404: Not Found would both be more truthy, and doing what it does now on error, which is outputting a custom page explaining what happened. And un-implementing this would cost about the same as implementing it: An hour?
    – L0j1k
    Apr 20, 2013 at 4:56
  • 1
    @L0j1k: HTML 5.0 just entered CR, not that that matters any. Apr 20, 2013 at 5:02
  • 10
    Considering that there is absolutely nothing on the backend that even indicates that something was deleted based on legal reasons, it would take a lot more than an hour to implement. All the system knows is "this question is deleted."
    – animuson StaffMod
    Apr 20, 2013 at 5:02
  • 4
    Even if the HTTP status code is not altered to 451 yet, the important thing is that the client has the reason explained to them. There isn't actually any specification which says that 404 pages must be useless and divulge no information whatsoever (Stack Overflow's could be more helpful, but GitHub's is the worst I know). Therefore, I suggest that the proposal should be that the user be informed of the reason in such cases (which would probably still require non-trivial backend modification), rather than that the response status code be 451. Apr 20, 2013 at 5:37
  • 9
    Out of curiosity, does anyone know which contribution in the example question n was challenged exactly? The question looks innocuous enough, at least under a copyright angle
    – Pekka
    Apr 20, 2013 at 5:38
  • 3
    @Pekka웃 Reading through that post, I indeed don't think it's the copyright angle that had them worried. I think they might have given this a shot for other reasons.
    – Bart
    Apr 20, 2013 at 8:46
  • 5
    @Bart yeah. This looks a lot like the company is abusing the DMCA system to get the embarrassing discussion taken down.
    – Pekka
    Apr 20, 2013 at 8:48
  • 4
    It doesn't really matter that 451 is officially approved. Google's request is intended to get 451 officially registered, but you can use it nevertheless. Just read the last paragraph of RFC 2616 section 6.1.1.
    – user168971
    Apr 20, 2013 at 9:13
  • 4
    @arjan Yes, it's still there, it's a normal mod deletion (by a SE employee). It's also everywhere on the internet, lots of people stepped up, grabbed the content from google's cache and hosted it on non US based servers.
    – yannis
    Apr 20, 2013 at 13:21

1 Answer 1


Alternatively, at least some more explanation could be returned with the 404, like is already done for other reasons such as:

  • [Your/This] question was removed from Stack Overflow for reasons of moderation

  • This question was voluntarily removed by its author [– that's you!]

As an aside: rather than some 403 Forbidden, currently anonymous users and users with less than 10k reputation get a 404 Not Found if they cannot see some content, even when others can see it. That might not fit the first line in RFC2616, but nicely fits the second line:

404 Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

Earlier, Stack Exchange has (rightfully so) refused to return 410 Gone instead of 404 Not Found, maybe as 410 explicitly says it is considered permanent.

  • 3
    Perhaps a 307 Temporary Redirect to a DMCA notice page would be appropriate?
    – Polynomial
    Apr 22, 2013 at 20:14

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