# Nginx/1.3.2 - 4xx responses are returned without HTTP headers, bug? **URL:** \ **Category:** NGINX\ **Created:** [July 9, 2012, 10:50am UTC](https://www.ruby-forum.com/t/nginx-1-3-2-4xx-responses-are-returned-without-http-headers-bug/221329 "2012-07-09T10:50:23Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![aris](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/258eb7/32.png) [@aris](https://www.ruby-forum.com/u/aris)\ **Post date:** [July 9, 2012, 10:50am UTC](https://www.ruby-forum.com/t/nginx-1-3-2-4xx-responses-are-returned-without-http-headers-bug/221329/1 "2012-07-09T10:50:23Z")
Hi, I think I stumbled upon a bug in nginx but I would like to get someone else’s opinion on this. It seems all 4xx errors are not prefixed by headers in HTTP responses. I have a simple test-script in bash which you can run to verify this behavior: function req { echo -n “GET /bugtest?id=”; for i in `seq 15000 17100` ; do echo -n “%7C$i” ; done ; echo -en “HTTP/1.1\nUser-Agent: Mozilla/5.0\nConnection: Close\nHost: [wiki.nginx.org](http://wiki.nginx.org)\r\n\r\n” ; } ; req | nc [wiki.nginx.org](http://wiki.nginx.org) 80 I can also reproduce this for other 4xx responses. My interpretation of the RFC is that this is unwanted, see > **[RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1](https://datatracker.ietf.org/doc/html/rfc2616)** > > HTTP has been in use by the World-Wide Web global information initiative since 1990. This specification defines the protocol referred to as "HTTP/1.1", and is an update to RFC 2068. \[STANDARDS-TRACK\] If this is not the appropriate place to report this please let me know as I couldn’t find a better place to report this. – Regards, Sjon Hortensius | React B.V. | [http://www.react.nl](http://www.react.nl) | Julianastraat 30 | 2012 ES, Haarlem | 023 553 90 00 ---
**Author:** ![Sjon\_Hortensius](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/a9a28c/32.png) [@Sjon\_Hortensius](https://www.ruby-forum.com/u/Sjon_Hortensius)\ **Post date:** [July 9, 2012, 11:53am UTC](https://www.ruby-forum.com/t/nginx-1-3-2-4xx-responses-are-returned-without-http-headers-bug/221329/2 "2012-07-09T11:53:06Z")
Hello! On Mon, Jul 09, 2012 at 10:41:19AM +0200, Sjon Hortensius wrote: > 17100` ; do echo -n “%7C$i” ; done ; echo -en “HTTP/1.1\nUser-Agent: > Mozilla/5.0\nConnection: Close\nHost: [wiki.nginx.org](http://wiki.nginx.org)\r\n\r\n” ; } ; > req | nc [wiki.nginx.org](http://wiki.nginx.org) 80 > > I can also reproduce this for other 4xx responses. My interpretation > of the RFC is that this is unwanted, see > [RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1 | RFC Editor](http://tools.ietf.org/html/rfc2616#section-6.1) Headers aren’t sent if nginx assumes the request is in HTTP/0.9 format. The above script makes nginx to think it’s HTTP/0.9 as uri used dosn’t fit into header buffer and nginx isn’t able to see “HTTP/1.1” before it returns 414. Maxim D. ---
**Author:** ![Sjon\_Hortensius](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/a9a28c/32.png) [@Sjon\_Hortensius](https://www.ruby-forum.com/u/Sjon_Hortensius)\ **Post date:** [July 9, 2012, 1:02pm UTC](https://www.ruby-forum.com/t/nginx-1-3-2-4xx-responses-are-returned-without-http-headers-bug/221329/3 "2012-07-09T13:02:04Z")
On 07/09/2012 11:52 AM, Maxim D. wrote: > > responses. I have a simple test-script in bash which you can run to > > Headers aren’t sent if nginx assumes the request is in HTTP/0.9 > format. The above script makes nginx to think it’s HTTP/0.9 as > uri used dosn’t fit into header buffer and nginx isn’t able to > see “HTTP/1.1” before it returns 414. > > Maxim D. Thanks for your reply! I have been looking for RFC documents describing the maximum request-length in HTTP/0.9, but I cannot find any. I found [http://www.w3.org/Protocols/HTTP/Request.html](http://www.w3.org/Protocols/HTTP/Request.html) (which links to [http://www.w3.org/Addressing/URL/5\_BNF.html](http://www.w3.org/Addressing/URL/5_BNF.html) to describe URLs) and [http://www.ietf.org/rfc/rfc1738.txt](http://www.ietf.org/rfc/rfc1738.txt), both of which describe no maximum length. If nginx assumes HTTP/0.9 for the request, it doesn’t seem very logical to return an error which cannot exist within that very protocol? – Regards, Sjon Hortensius | React B.V. | [http://www.react.nl](http://www.react.nl) | Julianastraat 30 | 2012 ES, Haarlem | 023 553 90 00 ---
**Author:** ![Sjon\_Hortensius](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/a9a28c/32.png) [@Sjon\_Hortensius](https://www.ruby-forum.com/u/Sjon_Hortensius)\ **Post date:** [July 9, 2012, 2:46pm UTC](https://www.ruby-forum.com/t/nginx-1-3-2-4xx-responses-are-returned-without-http-headers-bug/221329/4 "2012-07-09T14:46:39Z")
On Mon, Jul 09, 2012 at 01:01:21PM +0200, Sjon Hortensius wrote: > > > It seems all 4xx errors are not prefixed by headers in HTTP > > > [RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1 | RFC Editor](http://tools.ietf.org/html/rfc2616#section-6.1) > > > [http://www.w3.org/Protocols/HTTP/Request.html](http://www.w3.org/Protocols/HTTP/Request.html) (which links to > > > [http://www.w3.org/Addressing/URL/5\_BNF.html](http://www.w3.org/Addressing/URL/5_BNF.html) to describe URLs) and > > > [http://www.ietf.org/rfc/rfc1738.txt](http://www.ietf.org/rfc/rfc1738.txt), both of which describe no maximum > > > length. > > If nginx assumes HTTP/0.9 for the request, it doesn’t seem very logical > to return an error which cannot exist within that very protocol? Well, it does not return error. It just returns a page with text: “414 Request-URI Too Large”. What can you suggest to return for a request larger than configured buffer ? – Igor S. ---
**Author:** ![Sjon\_Hortensius](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/a9a28c/32.png) [@Sjon\_Hortensius](https://www.ruby-forum.com/u/Sjon_Hortensius)\ **Post date:** [July 10, 2012, 12:11pm UTC](https://www.ruby-forum.com/t/nginx-1-3-2-4xx-responses-are-returned-without-http-headers-bug/221329/5 "2012-07-10T12:11:57Z")
On 07/09/2012 02:46 PM, Igor S. wrote: > > > > of the RFC is that this is unwanted, see > > > > the maximum request-length in HTTP/0.9, but I cannot find any. I found > > > > a request larger than configured buffer ? > > > > When I said it returns an error I obviously meant it returns a HTTP > > > > error. Since HTTP/0.9 doesn’t define a maximum length for a URL, it > > > > seems strange to return an error about this very length in this specific > > > > protocol. I think the only problem I have with this behavior is nginx falling back to HTTP/0.9; a protocol which isn’t used on any network I know. I would prefer falling back to HTTP/1.0 which more clients will support, although I don’t know what impact this has. – Regards, Sjon Hortensius | React B.V. | [http://www.react.nl](http://www.react.nl) | Julianastraat 30 | 2012 ES, Haarlem | 023 553 90 00