# "404/"page not found": when/why "404" **URL:** \ **Category:** Factual Questions\ **Created:** [February 9, 2010, 5:10am UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241 "2010-02-09T05:10:25Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [February 9, 2010, 5:10am UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/1 "2010-02-09T05:10:25Z")
I found a bunch of “404”/“page not found” galleries and sites. But when was the expression first used, and why those numbers in particular? ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [February 9, 2010, 5:14am UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/2 "2010-02-09T05:14:30Z")
[404 error](http://en.wikipedia.org/wiki/HTTP_404#Overview) > [@](#): > > When communicating via HTTP, a server is required to respond to a request, such as a web browser’s request for an HTML document (web page), with a numeric response code and an optional, mandatory, or disallowed (based upon the status code) message. In the code 404, the first “4” indicates a client error, such as a mistyped URL. The following two digits indicate the specific error encountered. HTTP’s use of three-digit codes is similar to the use of such codes in earlier protocols such as FTP and NNTP. > > At the HTTP level, a 404 response code is followed by a human-readable “reason phrase”. The HTTP specification suggests the phrase “Not Found”[1] and many web servers by default issue an HTML page that includes both the 404 code and the “Not Found” phrase. > > A 404 error is often returned when pages have been moved or deleted. In the first case, a better response is to return a 301 Moved Permanently response, which can be configured in most server configuration files, or through URL rewriting; in the second case, a 410 Gone should be returned. Because these two options require special server configuration, most websites do not make use of them. > > 404 errors should not be confused with DNS errors, which appear when the given URL refers to a server name that does not exist. A 404 error indicates that the server itself was found, but that the server cannot retrive the requested page. ---
**Author:** ![Attack\_from\_the\_3rd\_dimension](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@Attack\_from\_the\_3rd\_dimension](https://boards.straightdope.com/u/Attack_from_the_3rd_dimension)\ **Post date:** [February 9, 2010, 5:24am UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/3 "2010-02-09T05:24:42Z")
Geek equivalent of “the lights are on, but nobody’s home” used to be to roll your eyes and mutter ‘404’ to your colleague. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [February 9, 2010, 5:29am UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/4 "2010-02-09T05:29:01Z")
Be thankful when you do get a 404 error. These days, spammers and hackers have most alternate spellings of popular domains allocated. Mistype drudgereport, amazon, or any other popular site and you’re playing Russian Roulette. There’s some nasty code traps out there. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [February 9, 2010, 10:40am UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/5 "2010-02-09T10:40:01Z")
It’s worth mentioning that response codes also happen when there is not an error - for example, response code 200 indicates that the HTTP request was received and accepted - the user doesn’t normally become aware of this, because it usually means the client (for example a web browser) can carry on and do what was asked of it (i.e. display a web page). ---
**Author:** ![psychonaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/psychonaut/32/4655_2.png) [@psychonaut](https://boards.straightdope.com/u/psychonaut)\ **Post date:** [February 9, 2010, 12:05pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/6 "2010-02-09T12:05:21Z")
Yep. Wikipedia also has an article covering [all the other HTTP status codes](http://en.wikipedia.org/wiki/List_of_HTTP_status_codes). ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [February 9, 2010, 12:36pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/7 "2010-02-09T12:36:30Z")
> [@psychonaut](#): > > Yep. Wikipedia also has an article covering [all the other HTTP status codes](http://en.wikipedia.org/wiki/List_of_HTTP_status_codes). So **that’s** what she meant by 413! ---
**Author:** ![psychonaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/psychonaut/32/4655_2.png) [@psychonaut](https://boards.straightdope.com/u/psychonaut)\ **Post date:** [February 9, 2010, 12:51pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/8 "2010-02-09T12:51:15Z")
> [@naita](#): > > So **that’s** what she meant by 413! You sure it wasn’t a 402? 🙂 ---
**Author:** ![DrFidelius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drfidelius/32/3447_2.png) [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)\ **Post date:** [February 9, 2010, 2:13pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/9 "2010-02-09T14:13:13Z")
> [@Attack\_from\_the\_3rd\_dimension](#): > > Geek equivalent of “the lights are on, but nobody’s home” used to be to roll your eyes and mutter ‘404’ to your colleague. Being a long-time geek, I must state that “404” as a geekism must post-date the introduction of “404” as an internet error message, and therefore cannot be the origin of the term. ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [February 9, 2010, 2:26pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/10 "2010-02-09T14:26:16Z")
> [@aceplace57](#): > > Be thankful when you do get a 404 error. > > These days, spammers and hackers have most alternate spellings of popular domains allocated. Mistype drudgereport, amazon, or any other popular site and you’re playing Russian Roulette. There’s some nasty code traps out there. Does anyone actually type things into their address bar anymore? That’s what Google is for. ---
**Author:** ![psychonaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/psychonaut/32/4655_2.png) [@psychonaut](https://boards.straightdope.com/u/psychonaut)\ **Post date:** [February 9, 2010, 2:33pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/11 "2010-02-09T14:33:54Z")
> [@Alessan](#): > > Does anyone actually type things into their address bar anymore? That’s what Google is for. Google doesn’t search intranets. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [February 9, 2010, 2:49pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/12 "2010-02-09T14:49:38Z")
> [@psychonaut](#): > > Google doesn’t search intranets. Surely any decently-made intranet should include navigable linked indexes and ideally, its own search engine? ---
**Author:** ![Rysto](https://avatars.discourse-cdn.com/v4/letter/r/ecccb3/32.png) [@Rysto](https://boards.straightdope.com/u/Rysto)\ **Post date:** [February 9, 2010, 2:50pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/13 "2010-02-09T14:50:22Z")
> [@aceplace57](#): > > Be thankful when you do get a 404 error. > > These days, spammers and hackers have most alternate spellings of popular domains allocated. Mistype drudgereport, amazon, or any other popular site and you’re playing Russian Roulette. There’s some nasty code traps out there. Generally you won’t get a 404 error if you try to visit an invalid domain. To get a 404 error you have to be communicating with an HTTP server, but if you try to connect to an invalid domain there is no HTTP server to talk to. ---
**Author:** ![psychonaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/psychonaut/32/4655_2.png) [@psychonaut](https://boards.straightdope.com/u/psychonaut)\ **Post date:** [February 9, 2010, 3:17pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/14 "2010-02-09T15:17:08Z")
> [@Mangetout](#): > > Surely any decently-made intranet should include navigable linked indexes and ideally, its own search engine? Of course. But I’m willing to bet that the non-decently made intranets outnumber the decently-made ones. 🙂 ---
**Author:** ![Attack\_from\_the\_3rd\_dimension](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@Attack\_from\_the\_3rd\_dimension](https://boards.straightdope.com/u/Attack_from_the_3rd_dimension)\ **Post date:** [February 9, 2010, 3:24pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/15 "2010-02-09T15:24:17Z")
> [@DrFidelius](#): > > Being a long-time geek, I must state that “404” as a geekism must post-date the introduction of “404” as an internet error message, and therefore cannot be the origin of the term. Wikipedia (the source of all approximate knowledge) gives a 2008 citation. I’m too lazy to look for more, considering how much dross the phrase 404 generates, however, apparently the [error codes were established](http://www.404errorpages.com/) in '92 ---
**Author:** ![IAmNotSpartacus](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@IAmNotSpartacus](https://boards.straightdope.com/u/IAmNotSpartacus)\ **Post date:** [February 9, 2010, 4:45pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/16 "2010-02-09T16:45:06Z")
> [@psychonaut](#): > > Google doesn’t search intranets. Yes, [it does](http://www.google.com/enterprise/search/gsa.html). ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [February 9, 2010, 4:55pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/17 "2010-02-09T16:55:10Z")
> [@IAmNotSpartacus](#): > > Yes, [it does](http://www.google.com/enterprise/search/gsa.html). No, it doesn’t. It’s clear to anyone with more than three brain cells that **psychonaut** was referring to Google’s public search service, not hardware search appliances that they sell to customers. But congratulations for realizing that a word can have different meanings in different contexts. I’m sure that feat made you feel super-l33t. ---
**Author:** ![HorseloverFat](https://avatars.discourse-cdn.com/v4/letter/h/8e8cbc/32.png) [@HorseloverFat](https://boards.straightdope.com/u/HorseloverFat)\ **Post date:** [February 9, 2010, 5:05pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/18 "2010-02-09T17:05:55Z")
These status codes are based on a kind of defacto unixy way of doing things. You’ll see these codes in smtp, ftp, etc. Generally 100-300’s means successful/message and 400-500’s mean error. Next time you fat finger someone’s email address, read the bounce message. It’ll probably be something like ‘550 - user doesnt exist.’ When TBL was writing the HTTP spec, he was just following old unix pricinples. ---
**Author:** ![Attack\_from\_the\_3rd\_dimension](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@Attack\_from\_the\_3rd\_dimension](https://boards.straightdope.com/u/Attack_from_the_3rd_dimension)\ **Post date:** [February 9, 2010, 5:09pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/19 "2010-02-09T17:09:52Z")
> [@HorseloverFat](#): > > These status codes are based on a kind of defacto unixy way of doing things. You’ll see these codes in smtp, ftp, etc. Generally 100-300’s means successful/message and 400-500’s mean error. Next time you fat finger someone’s email address, read the bounce message. It’ll probably be something like ‘550 - user doesnt exist.’ > > When TBL was writing the HTTP spec, he was just following old unix pricinples. Cool. Thanks. ---
**Author:** ![IAmNotSpartacus](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@IAmNotSpartacus](https://boards.straightdope.com/u/IAmNotSpartacus)\ **Post date:** [February 9, 2010, 5:14pm UTC](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241/20 "2010-02-09T17:14:46Z")
> [@friedo](#): > > No, it doesn’t. It’s clear to anyone with more than three brain cells that **psychonaut** was referring to Google’s public search service, not hardware search appliances that they sell to customers. Interesting that he then agrees there are intranets with “navigable linked indexes and ideally, its own search engine”… I guess taking the thread in context is too hard? Perhaps if you weren’t so quick to make ad hominem attacks you would have realized? > [@](#): > > But congratulations for realizing that a word can have different meanings in different contexts. I’m sure that feat made you feel super-l33t. Google does in fact search intranets, and in fact there are a number of large organizations that are using Google’s tool to do just that. I know this is hard to grasp. There’s no way to describe it in smaller words, though, sorry. [Next page](https://boards.straightdope.com/t/404-page-not-found-when-why-404/528241.md?page=2)