# "upstream sent too big header while reading response header from upstream"? **URL:** \ **Category:** NGINX\ **Created:** [February 3, 2016, 2:25pm UTC](https://www.ruby-forum.com/t/upstream-sent-too-big-header-while-reading-response-header-from-upstream/243999 "2016-02-03T14:25:12Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Sadaf\_N](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/858c86/32.png) [@Sadaf\_N](https://www.ruby-forum.com/u/Sadaf_N)\ **Post date:** [February 3, 2016, 2:25pm UTC](https://www.ruby-forum.com/t/upstream-sent-too-big-header-while-reading-response-header-from-upstream/243999/1 "2016-02-03T14:25:12Z")
Hi All. I am currently trying to find the source of “upstream sent too big header while reading response header from upstream” in my logfiles because nginx as a consequence returns “502 Bad Gateway”. Basically I used tcpdump to get the traffic and I compared two cases: 1. the communication is ok: 12167 07:03:51.466937 IP 10.10.3.7.80 \> 10.10.2.121.43817: Flags [P.], seq 1779345520:1779348777, ack 1001934214, win 219, options [nop,nop,TS val 2527240108 ecr 619023542], length 3257 12168 E…7.@.@… 12169 12170 … 12171 12172 .y.P.)j…p;.M… 12173 …$…HTTP/1.1 302 Found^M 12174 Content-Length: 58^M 12175 Content-Type: text/html; charset=utf-8^M 12176 Date: Wed, 03 Feb 2016 12:03:51 GMT^M 12177 Location: /^M 12178 Set-Cookie: rfid-mgt-console=… 12179 Set-Cookie: rfid-mgt-console.sig=xxx; path=/; expires=Wed, 03 Feb 2016 13:03:51 GMT; httponly^M 12180 Vary: Accept, Accept-Encoding^M 12181 X-Cf-Requestid: yyy^M 12182 X-Powered-By: Express^M 12183 ^M 12184 Moved Temporarily. Redirecting to / In this case everything up to “Moved T…” is in one response from upstream (10.10.3.7). 1. nginx throws mentioned error to error.log and returns 502 code 56874 06:31:45.307207 IP 10.10.3.7.80 \> 10.10.2.121.58073: Flags [P.], seq 953075345:953079441, ack 3028520986, win 219, options [nop,nop,TS val 2526758567 ecr 617097381], length 4096 56875 E…4…@.@… 56876 56877 … 56878 56879 .y.P…8…h… 56880 …F.$.(.HTTP/1.1 302 Found^M 56881 Content-Length: 58^M 56882 Content-Type: text/html; charset=utf-8^M 56883 Date: Wed, 03 Feb 2016 11:31:45 GMT^M 56884 Location: /^M 56885 Set-Cookie: rfid-mgt-console=… 56886 Set-Cookie: rfid-mgt-console.sig=xxx; path=/; expires=Wed, 03 Feb 2016 12:31:45 GMT; httponly^M 56887 Vary: Accept, Accept-Encoding^M 56888 X-Cf-Requestid: yyy 56889 06:31:45.307213 IP 10.10.2.121.58073 \> 10.10.3.7.80: Flags [.], ack 953079441, win 280, options [nop,nop,TS val 617097490 ecr 2526758567], length 0 56890 E…4…@.@.zw 56891 56892 .y 56893 56894 …P…8… 56895 $.)…F. 56896 06:31:45.307218 IP 10.10.3.7.80 \> 10.10.2.121.58073: Flags [P.], seq 953079441:953079542, ack 3028520986, win 219, options [nop,nop,TS val 2526758567 ecr 617097381], length 101 56897 E…@.@… 56898 56899 … 56900 56901 .y.P…8…JU… 56902 …F.$.(.503-564da79aecb5^M 56903 X-Powered-By: Express^M 56904 ^M 56905 Moved Temporarily. Redirecting to / In this case response from upstream (10.10.3.7) is much larger because of larger “Set-Cookie: rfid-mgt-console=…” returned and is divided into two parts. “upstream sent too big header while reading response header from upstream” is written to error.log. For clarity I only pasted the part of the traffic which differs. Initially in “http” section in nginx.conf: … http { proxy\_max\_temp\_file\_size 0; ``` proxy_buffering off; ``` … I tried to change it to: … http { proxy\_max\_temp\_file\_size 0; ``` proxy_buffering on; proxy_buffers 8 256k; ``` … And I also added: … proxy\_buffering on; ``` proxy_buffers 8 256k; ``` … to my “server” sections. I performed a restart but the error did not change. Can someone help me with this one? BR, Rafal. ---
**Author:** ![RafaSS\_Radecki](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/41988e/32.png) [@RafaSS\_Radecki](https://www.ruby-forum.com/u/RafaSS_Radecki)\ **Post date:** [February 3, 2016, 2:42pm UTC](https://www.ruby-forum.com/t/upstream-sent-too-big-header-while-reading-response-header-from-upstream/243999/2 "2016-02-03T14:42:44Z")
You want proxy\_buffer\_size. [http://nginx.org/en/docs/http/ngx\_http\_proxy\_module.html#proxy\_buffer\_size](http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffer_size) On Wed, Feb 3, 2016 at 2:24 PM, Rafał Radecki [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![RafaSS\_Radecki](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/41988e/32.png) [@RafaSS\_Radecki](https://www.ruby-forum.com/u/RafaSS_Radecki)\ **Post date:** [February 3, 2016, 3:10pm UTC](https://www.ruby-forum.com/t/upstream-sent-too-big-header-while-reading-response-header-from-upstream/243999/3 "2016-02-03T15:10:46Z")
Thanks, solved 😉 BR, Rafal. 2016-02-03 14:42 GMT+01:00 Richard S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):