There is no HTTP code for censorship (but perhaps there should be)

To quote Chris Applegate: "There is no HTTP code for censorship."
But perhaps there should be.

My ISP have recently been ordered to censor The Pirate Bay. They have done so unwillingly and, it would seem, have complied only with the letter of the ruling. Their block is, for now, trivial to circumvent.

I am concerned that this censorship will become more prevalent. As network neutrality dies, we will see more sites ordered to be blocked by governments who fear what they cannot understand.

However, chief among my concerns is the technical way this censorship is implemented. At the moment, my ISP serves up an HTTP 403 error.

$ wget -v
Connecting to||:80... connected.
HTTP request sent, awaiting response... 403 Forbidden

As far as I am concerned, this response is factually incorrect.

According to the W3C Specifications:

The 4xx class of status code is intended for cases in which the client seems to have erred.

Now, I haven't made an error when making this request. Furthermore:

The server understood the request, but is refusing to fulfill it.

In this case, the server did not even see the request. It was intercepted by my ISP and rejected by them on legal grounds.

The W3C aren't the only people who can define HTTP status codes - Twitter introduced the 420 code for example. Wikipedia has a fairly comprehensive list of HTTP status codes.

So, what HTTP code should ISPs - or others - serve up to indicate to the user that censorship is abound?



Request received, continuing process

This class of status code indicates a provisional response,


HTTP 112 - Emergency. Censorship in action.

Censorship is an Internet Emergency and should be treated as such.

112 is the emergency services number throughout Europe (may be confusing / irrelevant for non-Europeans).


This class of status code indicates that the client's request was successfully received, understood, and accepted.

Totally inappropriate. The request was not accepted - even assuming it was successfully received.


This class of status code indicates that further action needs to be taken by the user agent in order to fulfill the request.

Again, probably not appropriate (although one could argue that the user needs take action against her government or ISP).


As suggested by nabsltd on Slashdot the ISP could helpfully tell the user how to proxy around the censorship.

305 Use Proxy


The 4xx class of status code is intended for cases in which the client seems to have erred.

Normally, I'd be against placing the error here - however Microsoft have introduced the HTTP 450 status code "Blocked by Parental Controls"
450 - Blocked by Windows Parental Controls


HTTP 460 - Blocked by Repressive Regime.
(edit - IonOtter suggests the much more timely HTTP 451.>)


Response status codes beginning with the digit "5" indicate cases in which the server is aware that it has erred or is incapable of performing the request

This could be appropriate if it is the server which is performing the censorship. If Google was forbidden to show pictures to Tienanmen Square, for example.


HTTP 560 - Server is being censored.


There are currently no valid HTTP codes in the 9xx range. I am of the opinion that censorship is such an existential threat to the web that it requires


HTTP 911 - Internet Emergency. The provider of this connection is being forced to censor this request.

Of course, 911 is only the emergency services number in North America and other places but is sufficiently well known globally to be recognisable.

Pick A Winner

Choose an option or stick a comment in the box below.

Update 2012-06-12

The inimitable Tim Bray has submitted an RFC to the IETF HTTP working group for HTTP 451.
Ongoing discussion on Hacker News, Ter Verge, and in Spanish on meneame and ADSLzone, in Russian on habrahabr, in German on NetzPolitik, and in French.

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57 thoughts on “There is no HTTP code for censorship (but perhaps there should be)”

  1. says:

    Blocking the Pirate Bay is less censorship, more like kicking the dodgy bloke hawking ripped CDs out of the pub.

    A lot of people are in favour of the dodgy bloke. I have no idea why.

    The error codes were fun though!

    1. It starts with "bad guys" then it moves on to hate speech. Then political dissent. That's what we're seeing in China and Iran - is that what we want?

      1. kis says:

        not quite true, censorship on "bad guys" or hate speech isn't observed in China but political dissent.

  2. says:

    Trying to protect the creators of work of value (whether artists, musicians or software developers) doesn't automatically lead totalitarian states.

    That's a false dichotomy.

    The Internet isn't the whole world. People were able to overthrow dictatorships before the Internet, and they still can, whether or not Twitter exists, and especially whether or not the pirate bay exists.

    1. Hi Oli,

      Thanks for the comment. What I'm trying to get at is that this is the start of something I find worrying.

      The BT block is based on CleanFeed. This was originally set up to block images of child abuse. It's hard to have a rational discussion about blocking such sites - but I'll try!

      Firstly, CleanFeed has malfunctioned several times - most notably blocking Wikipedia.

      Secondly, it's very hard to determine which images should be banned. The Sun published topless photos of Sam Fox when she was 16. Today, that would be considered beyond the line.

      Thirdly, when CleanFeed was set up many people feared that it would be eventually used for other "objectionable" content. We were told we were paranoid. But, you can be paranoid and still be right!

      So now we have a situation where filesharing sites are considered as necessarily dangerous as child abuse and must be blocked.

      Even though there are artists and developers using The Pirate Bay for promoting their work (such as Dan Bull) the whole site is now considered illegal.

      How much of a site has to be illegal before it's banned? I notice a blog post of yours which contains musical notation and an image neither of which you own the copyright to.

      I honestly believe that this is how it starts. Yes, you can organise a protest or overthrow a government without the Internet - but it is harder. Much harder.

      It's dangerous for me to use the slippery slope argument, I know, but this has actually happened in Iran and China.

      Do you really think it can't happen here? And if it does happen here, are you happy to do without Twitter, Facebook, BBC News - all on the say so of a Judge?


  3. says:

    Haha, yes, I think you'll find my use of the Eurythmic's riff comes under 'fair use' and I'm not actually infringing copyright by presenting it there. If I was charging for it, then I think I'd have a problem. And if I was giving away the exact digital bits (mechanical copyright) that was owned by the record label, again that would be an issue.

    The equivalent of whistling a pop tune is not something people generally get prosecuted for!

    This is all catered for in existing copyright laws.

    And I don't think Google have copyrighted their image of their synth. And given that I clearly state the originating site and am not profiting from it - or depriving Google income by it's use, I don't think you can hoist me on that petard! (Though if I'm wrong, that would be interesting)

    Just because it's difficult to draw a neat line around what is objectionable and what is not (re the image issure you raised of Sam Fox), it doesn't mean that we can't all agree what is wrong and what is right.

    A lot of internet people have decided that it is right to take other people's work and share it without the originator's permission. I fundamentally disagree with that stance. Imagine if I pick up an apple for 'free' from the ground and then you take it from me without asking - that is wrong. (The twist with digital files in that I still have a copy of that apple. I think that is irrelevent. The one you have taken still has value, and you have still taken it without asking. If nothing else, it's just rude!).

    The spectre of 'states' controlling the internet is another weird thing. I'm pretty sure any freedom loving technologists are always going to work out a way to communicate without the state eavesdropping. I'm sure you'd agree that they're smart enough for that! If a state is a fascist, there are a lot more problems there than banning Twitter.

    I'm sure Dan Bull can find other ways of distributing his content - one artist legimately using an illegal site doesn't legitimise that site.

    And remember, 'information wants to free' is not the whole quote. I think we would both agree with the full statement:

    "Information wants to be free. Information also wants to be expensive. Information wants to be free because it has become so cheap to distribute, copy, and recombine - too cheap to meter. It wants to be expensive because it can be immeasurably valuable to the recipient. That tension will not go away. It leads to endless wrenching debate about price, copyright, 'intellectual property', the moral rightness of casual distribution, because each round of new devices makes the tension worse, not better."

    1. Well, you make a number of interesting points. Firstly, The Pirate Bay aren't charging for access. True, they make money from advertising - but you make money by using your website as a portfolio.

      Copyright is automatic - so the image of the synth does belong to Google. The bottom of the site clearly says "© Google".

      Your linking has nothing to do with it. Most of the torrents on TPB link to Amazon, iMDB or similar.

      Yes, geeks like me can always circumvent blocks - but we shouldn't have to. Why should non-technical people be blocked? Why should we risk legal sanctions for helping people less fortunate than ourselves?

      The are lots of artists using TPB - and other sites. Why should a government say which we can and cannot use? There are lots of people using WordPress for unsavoury blogs - if the government bans the site, your blog will disappear with all the others. Nevermind, you can just use another site...

      You say "If a state is a fascist, there are a lot more problems there than banning Twitter."

      Indeed there are - but the banning of certain sites, the demonising of particular ideas, is one of the first steps down that path. Neither you nor I want to end up living in a system where the government can capriciously ban anything it deems not in the public interest.

      Like you, I wish TPB didn't exist and that artists receive a fair payment for their work. I just don't think these draconian measures are the way to do it. Worse, I fear that they will lead to something more sinister.

      That's why I'm trying to kick up a fuss.

  4. Chris B says:

    "governments who fear what they cannot understand."

    Sorry, what isn't understood? Is there some depth to TPB we're missing?

    Firstly, you're suggesting that blocking access to TPB is a slippery slope that may lead to blocking the BBC News. Do you know how ridiculous that sounds? It's as churlish as trying to tie it to political censorship. As Oli offered you so politely, you're trying to equate an activity that costs the country money and art with fascism - but what of your own fascist beliefs?

    It's you, not the State, that wants to limit peoples personal freedoms, by allowing sites that damages the economy, artists, developers, designers and other content creators careers. If there's any slippery slope here it's to Freesville, where only huge multinationals profit from the work of the individual creator. Your position on copyright seems to be a lot closer to that of China and Iran's than the UK defending copyright holders - you should consider that before you start rolling down slippery slopes.

    "Even though there are artists and developers using The Pirate Bay for promoting their work (such as Dan Bull) the whole site is now considered illegal."

    That is the most bizzare defence of the Pirate Bay I've ever seen; your argument is as credible as Dan Bull is a rapper, and actually delivers good proof of the antithesis. Dan Bull is a shield to say "hey, we know people use this facility to rob the work of others, but we help real artists, like this talentless rapper chap". Why aren't there any real MC's on this site? Because talented people need to get paid for their work - not robbed; because talent takes time and time takes money. If we allow TPB instead of DOOM or Chuck D we'll wind up with poorly developed trash like Dan Bull. HAVE YOU SEEN HIS LYRICS? IS THAT WHAT YOU WANT FOR YOUR KIDS?! You may want a world full of lightweight talentless nonsense; I'd rather the professionals were given a chance to develop and get fairly paid for their work.

    If it weren't for music, I, and many others I've met, would probably of had a life of crime. If you want to put your rights to take over my rights to make then we've got a problem - if we all join your game then there will be nothing of any worth to take.

    "How much of a site has to be illegal before it’s banned?"

    Isn't 99.9% enough for you? How about 99.9% and a Dan Bull?

    "I honestly believe that this is how it starts"

    Yes, Fahrenheit 451 is just around the corner. Your beliefs are as justified and true as that of any religious zealot, and you've made that perfectly clear on this page. OTOH, your sincerity is sadly not in doubt.

    1. Wow... that's... ok.


      TPB evidently does have depths. It's used as a message board, hosts censored documents and, in several countries, has a strong political following.

      Fascism is the subservience of the state to commerce (among many other factors). Look at the intense money and lobbying behind DEAct and SOPA.

      You are confused when it comes to freedoms. I am not trying to cripple the economy - nor prevent anyone from making a living.

      With regard to the artistic merits of Dan Bull (or any of the hundreds of other artists promoting their work on TPB, YouTube, or MegaUpload) - it's hardly worse than TOWIE, is it? That's not much of an argument.

      Finally, take a look at the continual drone warfare, the conservative politicians who want to reverse decades of reproductive health gains, the protests on our streets, the privatisation of the police and NHS.

      That, to me, looks like creeping fascism.

  5. Chris B says:

    My comment is apparently awaiting moderation and my email address will not be published! What sort of censorship is this?! You should have a code for this scenario - stick 560 up on the page when we click POST COMMENT.


    ...slippery slope...

  6. Oli says:

    Interesting conversation!

    I think actually several things are being conflated here:

    1. Copyright law.
    I think the Pirate Bay are wrong to distribute music & film they don't own the rights to. The law of our land holds that creators are allowed to profit from their work. The Pirate Bay disagree and chose to break the law. Which side of that argument are you on Terence? It's not clear to me.

    Further, as TPB are breaking the law, it's within copyright holder's rights to prosecute and/or seek those sites' closure.

    2. Blocking websites
    Child abuse sites should be taken down when found. It's about right and wrong. Most people would agree it's wrong, so it should be tackled. I'm happy for ISP's to block that material wherever and however possible. And I accept that there's the risk of an occasional false positive and the accidental removal of a legal site (such as the temporary Cleanfeed / Wiki incident).

    3. Fascism
    "That, to me, looks like creeping fascism.", "Fascism is the subservience of the state to commerce".
    No. It really - really - isn't.
    Read about Nazi Germany in the '30s. Murder of politial rivals. Institionalised racism, oppression, and thuggery. That's Fascism. A centre-right party doing badly thought out reforms of the NHS is not fascism. That's is really insulting to the millions of victims of fascism throughout history.

    Fascism is a horrible thing and I think the left here in the UK throw it around far, far too easily without realising what they're saying.


    Conflating all these leads to confused arguments. I think we can resolve point 1 easily enough - do you download copyrighted material? That answers your stance there easily enough.

    Point 2: I personally don't buy the slippery slope argument of ISPs blocking first abuse sites and then suddenly deciding to block the wikipedia page about democracy. We're not China or Iran and never will be. You might think this complacent, but the political system here has come from a different place than those countries and we're not likely to suddenly end up there.

    Point 3: let's stop throwing the F word around; it's irrelevant for the most part.

    1. Alan says:

      "I think the Pirate Bay are wrong to distribute music & film"

      -- TPB don't distribute anything. You don't download anything from TPB except a pointer. The porn, music, Linux ISOs, etc, are on other users' PCs.

      This is not a trivial distinction. It's the same thing that protects Google and Yahoo from prosecution for things you find via their sites.

      "Further, as TPB are breaking the law"
      -- If they were "breaking the law" they could be prosecuted and shut down. Many attempts to do this have failed to prove they are in fact "breaking the law.
      Blocking the site rather than having it taken down is an admission of this.

  7. ChrisB says:

    >"I just don’t think these draconian measures are the way to do it."

    So, what's your answer? If we all agree that TPB is bad, and wish it out of existence, what is so wrong with it not existing? I think it's something to do with this :

    >"Worse, I fear that they will lead to something more sinister."

    More sinister than anonymously run commercial enterprises outside of all normal legal jurisdictions that takes pride in being accountable to nobody? More draconian than forcing normal people to pay more tax because of falling tax revenues? How much money does the UK have to lose before it crosses your line? What cost is too much for you? Schools? Hospitals? We're in a recession, again, we're fighting hard to keep ourselves afloat and you're moaning about http error codes on TPB. What about my freedom to feed my family? My rights to sell my work in an open and fair market?

    >"That’s why I’m trying to kick up a fuss."

    ...about HTTP error codes - I see your logic...they close an unscrupulous establishment and you complain about the sign on the door!

    >With regard to the artistic merits of Dan Bull...
    >it’s hardly worse than TOWIE, is it?
    >That’s not much of an argument.

    I hope you were referring to your previous line, if so I agree - it's not much of an argument, why would we measure human artistic endeavour against TOWIE? Do you assess a lot of things this way? If there is some great free art by TPB members post it here and demonstrate, hopefully it'll be of a higher standard than your prior example. Either way, I think these fringe cases (budding politicians and musicians) will find another platform just fine, maybe more appropriately titled for their respective causes. If you're going to TPB for the politics and musicians, I can recommend some alternatives that might be a better fit, but I suspect you already know this was a bit of bluster.

    >"Fascism is the subservience of the state to commerce"

    No it isn't, that's a plutocracy; according to Wikipedia - "Fascists advocate a state-directed, regulated market economy that is dedicated to the nation; the use and primacy of regulated private property and private enterprise contingent upon service to the nation". Which sounds a lot like the argument against IP put forth by TPB supporters to me (all IP should be available to and for "the people"). It's no coincidence that regimes that don't respect or protect IP are also the most authoritarian, so before you tell us that the UK is on a slippery slope to becoming like China or Iran, consider their position and record on IP protection.

    >"That, to me, looks like creeping fascism."

    That's because of your fallacious definition of fascism! To me, it looks like nothing to do with this issue and a distraction from the fact that you'd rather the government didn't prevent access to a site that's primary raison d'être is to distribute other peoples work for free, illegally. I'm sure you've got your reasons, but I don't think you've articulated those yet, you've just stated that there are some legit uses for Pirate if a crackhouse had a Citizens Advice Bureau attached you'd argue it was wrong to close it? It's called "The Pirate Bay", it's where you can get pirate stuff - I don't see where the confusion comes from. You're against it, but you don't want to stop access to it, because Dan Bull and some political activists will have to find another forum?

    ...and you say I'm confused. 😀

    >"Me choosing to moderate comments is not censorship."

    Then why do it? Don't you want to censor blog spam, etc? I think you've got every right to censor/moderate your comments, but I also think democratic government has a right to moderate the internet when it's against the interests of citizens. When you do it, it's OK, but when a state does it there's something inherently wrong/evil/draconian - slippery slope, according to you. I think you're both entitled and it'll probably result in better quality content if you do...I don't want to read blog spam any more than you do.

    Also, what exactly do you think is being censored by preventing TPB access? All of the stuff on Pirate Bay is available elsewhere, maybe asides some commentary that's completely free to migrate wherever the content owners choose. Censorship is preventing free speech or communication, not stopping people from torrenting stuff - you can purchase the stuff elsewhere and there are plenty of internet forums to discuss the revolution in. There's no evidence the government is trying to stop free speech or communication, just prevent some piracy, get some tax revenues in. I think a lot of this is in your head and bears no relation to reality - they're not trying to stop the forums, just the torrents.

    Regarding your understanding of the Google/copyright/Moog situation : in the US and the UK Oli could claim fair use because "the effect of the use upon the potential market for or value of the copyrighted work" was negligible; his usage made no difference to Google, financially. Had they of been selling the image, and/or clearly marked it as being protected he would be in a different position, but that wasn't the case. This is an error you've arrived at because you seem to think that absolutes are the only way forward - it'll either be completely unregulated or it's 1984. Maybe things will be reasonable and the government will merely seek to optimise its tax take from UK digital companies, is that so hard to believe?

    Your view is implicit in the language you employ; you consistently use negative words (probably internally and externally) to skew your perspective. If you look at those words (draconian, fear, censorship, creeping, etc) carefully you'll find them fairly meaningless in the context you're attempting to apply them - they convey no meaning without direct proof of the suggested intent; they're simply scaremongering, and that's obscuring very real issues here. I still don't understand, I think I've made my point clear but I'm still no further to understanding yours yet, only that you're afraid of something that you call fascism; by which you actually mean the limiting of individual freedoms by the state because of pressure applied by commerce, right? Yet in the instance you've given, you've agreed that these freedoms hurt the freedoms of others (content creators)? I assume you'd agree that a freedom or right that allows you to hurt others is not really an appropriate right to have? Then what is your point?

    I think the government is simply trying to prevent counterfeit goods, as it has done for much of the past 400 years - everything else is a reflection of your psyche; and that's the bit that interests me. If they try and close Twitter, I might think you've got a point and we'll rise up against those nasty fascists together, but with TPB the clue is in the name.

    An enjoyable discussion, nonetheless. Liked your Martin Niemöller thing, ironically very trade union - but we're not in Nazi Germany, thanks in part to UK Intellectual Property!

  8. says:

    The only thing is, why would the gov't want their citizens to know that their being censored?

    That aside, I'm quite partial to error code 1984.

  9. Red says:

    I think you suggestion is very insightful. The problem isn't really why entities are censoring requests in transit. (Those could be rationalized till the cows come home.) The problem is that as a client, you have no way of determining if one of the internet's series of "tubes" is lying to you.

    If I had to vote for one of the above suggestions "451" would be me choice. However, for orthogonality I would propose a 600 code series that would indicates you are receiving a response that originated from a proxy rather then the true destination server.

    In this case 603 Ain't Gonna Get It, would seem most appropriate.

  10. Whatever anyone thinks about the appropriateness of blocking access to TPB, the error code returned by the ISP is fraudulent. It is a message purporting to come from TPB, when in fact it comes from another agent intercepting packets directed to TPB. I am pretty sure that HTTP has no provision for messages not authorized by the server they purport to come from. An ISP has no business manufacturing a fraudulent response from a site that does not belong to it.

  11. says:

    I actually like 451, since it basically describes what they are trying to do. This is a digital book burning.

    The Pirate Bay is a digital library. Possibly the greatest library humanity has ever had in terms of content. Just like physical libraries, they can buy content once and share it with many people. Librarians have been fighting off content authors with malicious intent for years, it's time the Internet generation does the same.

    1. Chris B says:

      "The Pirate Bay is a digital library. Possibly the greatest library humanity has ever had in terms of content"

      No it isn't, as the guy said above, none of the content is stored on the site (only the magnet links, etc); closing TPB doesn't effect the content at all (asides the forums, which an afternoons LibCURL could fix).

      "This is a digital book burning."

      Again, completely untrue, for the same reasons. I'm surprised how few people commenting on TPB have the first clue as to what it actually is.

      "Librarians have been fighting off content authors with malicious intent for years"

      Seriously? My mate's a librarian, she seems to spend her time organising authors for reading/signing session, or fighting to stay open, not fighting off malicious content owners. Authors have fought to keep libraries open. Clearly libraries are different around your way.

      A lot of replies from folk that seem to think the sign on the door is the problem, not the fact that the Pirate Bay is one of the most illiberal and repressive organisation the internet has come up with, taking the rights and work of millions of normal working people and making a mockery of them.

      I think there should be a new error code, I don't care what it is, because it doesn't really matter to me. Terence didn't start this campaign when they started blocking child porn sites. Hopefully that's because he doesn't frequent those sites; I'd suggest the same applies here. This only matters to you if you use TPB, and you only use TPB if you're thieving stuff or genuinely enjoy chatting to 14 year old northern European boys about why everything should be free. Terence says it also has Dan Bull and politics, but I doubt that's a big draw (his name isn't in Dan's video of people that paid).

      Whatever code is chosen, I probably won't be seeing it, it's a problem pirates and child porn fanatics are going to have, and I have little sympathy for either.

      Another day, no real answers to any of the questions here, but a lot of suggestions about a 3 digit HTTP error code. My personal vote goes to 321, with a styled FBI graphic but surrounded by flowers and a picture of Ted Rogers & Dusty Bin.

  12. Hymer X. says:

    But the answering server is not the server the request was sent to and the request would never reach the intended server. "2xx The request has been processed by alternate server due to illegal content on intended server."

  13. S0litaire says:

    Like the old joke goes: 665-667 the neighbourhood of the beast

    How about something like:

    665 : censored by a commercial or non-governmental body (e.g. UK's Cleanfeed system / I.W.F. or your Provider blocking access to legal / competing content.)

    667 : censored by Government or by Legal Order

  14. Oli says:

    >“I think the Pirate Bay are wrong to distribute music & film”

    – TPB don’t distribute anything. You don’t download anything from TPB except a pointer. The porn, music, Linux ISOs, etc, are on other users’ PCs.

    You're splitting hairs Alan. They allow access to material their copyright holders have not agreed to.

    By arguing this point, you're basically saying you're ok with TPB distributing other people's work. Fine,
    your position is clear enough on that.

  15. Steve says:

    People are right. TPB isn't like a library as it doesn't host any content itself, merely pointers. Indeed, TPB may merely be the greatest card catalog in human history.

    (Okay, probably not.)

  16. Chris B says:

    It's all gone a bit "Night Of The Living Technocrat" around here; there's something very odd about this conversation, its timings and responses. Asides myself and Oli (who clearly agree) nobody seems to have any interest in the subject at hand. It's all so meta that there's no content.

    The post is based on a false premise, that blocking TPB is censorship, but censorship is when you stop free speech or communication, and that's not what the block does (Terence is free to communicate anywhere, except on servers whose primary function is to help distribute illegal material, where communication can become collateral damage). His argument regarding politics and Dan Bull is akin to the people that said "what about all the legal stuff on Megaupload?" or the classic "what about all the good things Hitler did?".

    Terence has done little to engage the discussion, answer any of the relevant points or explain his position. As such, I can only assume this is because he uses TPB for stealing the work of others himself, has lied on this thread and got some mates in to try (unsuccessfully) to distract from that.

    Which is all most unfortunate, and makes me think less of him. Be seeing you. 🙂

  17. says:

    Yeah, I was hoping for a bit more of a discussion around the points raised, as they are interesting and important.

    It's also interesting that no one on the 'information wants to be free' side has come right out and said that they download illegal material, or even tried to make the argument that it's not illegal (as some deluded Pirate Party types try - and fail - to claim).

    Perhaps they're ashamed now they've realised the disrespect it shows to the creators whose work they enjoy enough to steal, but not to pay for.


    On the plus side, I enjoyed Terence's optical theremin idea. Though I think he might be infringing some of John Cage's alleatoric music concepts! 😉

    1. Hi Chris, Oli,

      Sorry for my lack of replies. As you can see from my other posts, it's been a busy weekend for me!

      I'd like to make three final points.

      1) The primary purpose of this blog was to talk about the technical measures behind blocking. I'm sorry that it descended to the level of mere politics.

      2) Whether or not you think blocking a site which has not been found to be illegal is censorship, I think it's important to talk about these things before it's too late.

      3) Finally, I've been quite open on this blog about my past breaches of copyright and where I think the creative industries have made mistakes.

      There appears to be a thriving discussion on Slashdot and MetaFilter.

      Thanks for your comments.


  18. Alex says:

    Vote for 'Other' is a second for 451: Site not permitted in your country.

  19. ChrisB says:

    1) The title of the post uses the word censorship. I think I've demonstrated that no such thing is happening here.

    2) Again, another misunderstanding - the Pirate Bay and it's users HAVE been found to be breaking UK law in court. Justice Arnold gave written judgment in February - "In my judgment, the operators of TPB do authorise its users' infringing acts of copying and communication to the public. They go far beyond merely enabling or assisting. I conclude that both users and the operators of TPB infringe the copyrights of the claimants in the UK."

    3) You sound like you endorse piracy and think blocking TPB is censorship. You've not made your position at all clear, you could try to answer some of the questions raised in this thread because you've still left this thread with the insinuation that the government is dark and evil, but TPB are bastions of free speech and art.

    It just isn't so.

  20. Oli says:

    heheh, 'mere politics'!

    Yes, we picked up on the trivial aspect of the mere destruction of the creative industries, when in fact it's the error codes returned by illegal sites which are the real issue here!

    Tho, to be fair, that was what you were trying to talk about in your post. BUT! You claimed censorship. Attempting to stop illegal sharing is not censorship. That, and some other schoolboy errors in this debate, is what has irked Chris & I.

    Yes, this debate is raging on other sites, but you have stimulated the conversation here as well. Well done!

    I shall now read the links you provided.

    1. Ne says:

      Hi Tim. Awesome choice of the error code. May be you could ammend it to include some sort of reference to the censored data like this:

      451 Unavailable for Legal Reasons of Resource magnet:?xt=urn:ed2k:354B15E68FB8F36D7CD88FF94116CDC1&xl=10826029

      That way would be more transparent what is being censored if providing that info is not also censored. 😉

    2. klg says:

      Although this probably is a misinterpretation of your intents (I surely hope it is), but using 4xx range looks like you're actually advocating censorship. You're telling user agents that it's their error to make the request. ISP blocking access sets up a proxy that refuses to serve the request, it fails at their end, therefore code should be in 5xx range.

  21. Martin says:

    We already referenced this problem in 1997 in a paper:

    If a huge number of computers or individual pages is blocked, neither the individual operator of a computer nor the individual user will know whether there is a technical defect that can be eliminated or whether some content has been blocked.

    The 451 does not really fix this problem but for a protocol and application specific implementation.

    Funny thing is: government paid us to write this paper but hasn't understood it even 15 years later.

  22. klg says:

    ISP blocking access in this way acts as a proxy, and proxies are servers themselves or act on behalf of the servers so they use 5xx codes for their errors. Now using code in 4xx range for censorship actually shows that your ISP haven't done this unwillingly only because they were forced to do so. They tell you that YOU are in error by even sending this request, they say it's illegal for you to request this page. Is that right? Tomorrow you'll be forbidden to even think about it.

    You see, choice of code in 4xx or 5xx range in case of censorship is an ideological issue, not a technical one. I'd use 5xx, because it's a proxy's problem that it cannot fulfil the request even though it was deliberately set up just to refuse it. I don't like 451 only because it lies in 4xx range and Tim Bray's I-D should be revised unless IETF advocates censorship itself!

  23. .tomi says:

    4xx are client-side errors, so it's not the case.
    5xx are server-side errors, so they're wrong too.
    1xx seems like a good option, but then they MUST NOT have a message-body IIRC.
    2xx seems like a good choice. The request was processed, understood, and accepted. It's just not the origin server that processed it.

    Although, a mechanism for telling that the response has not been sent from the origin server is needed here. This could be done by a header with the hostname of the machine that is responding, like '"Processed-By" ":" host'.

    1. .tomi says:

      How I love it when there's no edit options...

      I made a mistake there. It's not that it wasn't the origin server. It's that the origin server is not the one intended.

    2. klg says:

      2xx is inappropriate because request is not accepted even if it's understood and processed as stated in the original post. Using 2xx code implies that the request is successfully fulfilled, i.e. in case of GET, requested resource is returned in body.
      As I stated in previous comment, ISP that blocks the request in this manner can be understood as a forced proxy and therefore 5xx is fine (server's error as in remote error, not made by client, cf. 502 and 504 codes).

  24. says:

    Personally, I like error code: "2009". That's the code for the year Obama was allowed to enter and rent The White House resulting in the cause for this ridiculous debate to occur in the first place.

    1. I've approved this comment merely because it's so wide of the mark it's hilarious!
      I had no idea that Obama started censorship in the UK. Truly he is a cunning devil...
      Extra points for having a 4 digit HTTP code.


Trackbacks and Pingbacks

  1. [...] The HTTP Statuscode 451 (see came out of a discussion in the blog of +Terence Eden -, [...]

  2. [...] also credits Terence Eden, a well-known mobile software manager, for pointing out that there are no good Web error messages for censorship. Eden had noticed that when he tried to get The Pirate Bay, a BitTorrent file sharing site [...]

  3. [...] 这并不是一个新问题,Tim Bray特别感谢了不久前一位开发者提出的没有专门针对审查机器的HTTP代码。而早在2008年,就已经有人指出这样的问题,但直到现在,才有Google出面试图为网站开发者和网民解决这样的难题。 [...]

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