<div dir="ltr">Hi all,<br>I've got a "strange problem" with varnish 4.1.3 with error 503 after a backend response with 304<br><br>I believe my mistake is that i try to cache a URL for which the backend send 304 response and that is something unallowed.<br><br>Is that correct?<br>If not was where is the problem?<br><br>Regards<br>Yiannis<br><br>p.s I do not have the same problem with varnish 4.0.2<br><br>The details from varnishlog<br><br>*   << Request  >> 721018<br>-   Begin          req 721017 rxreq<br>-   Timestamp      Start: 1468531337.961047 0.000000 0.000000<br>-   Timestamp      Req: 1468531337.961047 0.000000 0.000000<br>-   ReqStart       192.168.50.80 55518<br>-   ReqMethod      GET<br>-   ReqURL         /event/diff?id=707658&rev=925&country=ES&LANG=en&xfarm=2&_=1468531333090<br>-   ReqProtocol    HTTP/1.1<br>-   ReqHeader      Host: <a href="http://www.xxx.ge">www.xxx.ge</a><br>-   ReqHeader      X-Forwarded-For: 192.168.55.145<br>-   ReqHeader      X-Forwarded-Proto: https<br>-   ReqHeader      Connection: close<br>-   ReqHeader      Accept: */*<br>-   ReqHeader      X-Requested-With: XMLHttpRequest<br>-   ReqHeader      User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36<br>-   ReqHeader      Referer: <a href="https://www.xxx.ge/event/index/707658">https://www.xxx.ge/event/index/707658</a><br>-   ReqHeader      Accept-Encoding: gzip, deflate, sdch, br<br>-   ReqHeader      Accept-Language: en-US,en;q=0.8,el;q=0.6<br>-   ReqHeader      Cookie: __cfduid=d6091c5456123ad4d97ceda2ab91445248766; LANG=en; walkthrough=1; LANG=en; _cb_ls=1; optimizelyEndUserId=oeu1459345286386r0.9749153622397837; optimizelySegments=%7B%225389070408%22%3A%22false%22%2C%225372042113%22%3A%22gc%22%2C%225391<br>-   ReqUnset       X-Forwarded-For: 192.168.55.145<br>-   ReqHeader      X-Forwarded-For: 192.168.55.145, 192.168.50.80<br>-   VCL_call       RECV<br>-   ReqUnset       Cookie: __cfduid=d6091c5456123ad4d97ceda2ab91445248766; LANG=en; walkthrough=1; LANG=en; _cb_ls=1; optimizelyEndUserId=oeu1459345286386r0.9749153622397837; optimizelySegments=%7B%225389070408%22%3A%22false%22%2C%225372042113%22%3A%22gc%22%2C%225391<br>-   ReqHeader      Cookie: __cfduid=d6091c5456123ad4d97ceda2ab91445248766; LANG=en; walkthrough=1; LANG=en; _cb_ls=1; optimizelyEndUserId=oeu1459345286386r0.9749153622397837; optimizelySegments=%7B%225389070408%22%3A%22false%22%2C%225372042113%22%3A%22gc%22%2C%225391<br>-   ReqURL         /event/diff?id=707658&rev=925&country=ES&LANG=en&xfarm=2<br>-   ReqUnset       Cookie: __cfduid=d6091c5456123ad4d97ceda2ab91445248766; LANG=en; walkthrough=1; LANG=en; _cb_ls=1; optimizelyEndUserId=oeu1459345286386r0.9749153622397837; optimizelySegments=%7B%225389070408%22%3A%22false%22%2C%225372042113%22%3A%22gc%22%2C%225391<br>-   VCL_return     hash<br>-   ReqUnset       Accept-Encoding: gzip, deflate, sdch, br<br>-   ReqHeader      Accept-Encoding: gzip<br>-   VCL_call       HASH<br>-   ReqHeader      X-defHash: /event/diff?id=707658&rev=925&country=ES&LANG=en&xfarm=2<br>-   ReqUnset       X-defHash: /event/diff?id=707658&rev=925&country=ES&LANG=en&xfarm=2<br>-   ReqHeader      X-defHash: /event/diff?id=707658&rev=925&country=ES&LANG=en&xfarm=2 + <a href="http://www.xxx.ge">www.xxx.ge</a><br>-   VCL_return     lookup<br>-   VCL_call       MISS<br>-   VCL_return     fetch<br>-   Link           bereq 721019 fetch<br>-   Timestamp      Fetch: 1468531337.963143 0.002097 0.002097<br>-   Timestamp      Process: 1468531337.963165 0.002118 0.000021<br>-   RespHeader     Date: Thu, 14 Jul 2016 21:22:17 GMT<br>-   RespHeader     Server: Varnish<br>-   RespHeader     X-Varnish: 721018<br>-   RespProtocol   HTTP/1.1<br>-   RespStatus     503<br>-   RespReason     Service Unavailable<br>-   RespReason     Service Unavailable<br>-   VCL_call       SYNTH<br>-   RespHeader     Content-Type: text/html; charset=utf-8<br>-   RespHeader     Retry-After: 5<br>-   VCL_return     deliver<br>-   RespHeader     Content-Length: 280<br>-   Storage        malloc Transient<br>-   Debug          "RES_MODE 2"<br>-   RespHeader     Connection: close<br>-   Timestamp      Resp: 1468531337.963247 0.002200 0.000082<br>-   ReqAcct        1077 0 1077 205 280 485<br>-   End<br><br><br>*   << BeReq    >> 721019<br>-   Begin          bereq 721018 fetch<br>-   Timestamp      Start: 1468531337.961169 0.000000 0.000000<br>-   BereqMethod    GET<br>-   BereqURL       /event/diff?id=707658&rev=925&country=ES&LANG=en&xfarm=2&<br>-   BereqProtocol  HTTP/1.1<br>-   BereqHeader    Host: <a href="http://www.xxx.ge">www.xxx.ge</a><br>-   BereqHeader    X-Forwarded-Proto: https<br>-   BereqHeader    Accept: */*<br>-   BereqHeader    X-Requested-With: XMLHttpRequest<br>-   BereqHeader    User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36<br>-   BereqHeader    Referer: <a href="https://www.xxx.ge/event/index/707658">https://www.xxx.ge/event/index/707658</a><br>-   BereqHeader    Accept-Language: en-US,en;q=0.8,el;q=0.6<br>-   BereqHeader    X-Forwarded-For: 192.168.55.145, 172.16.50.80<br>-   BereqHeader    Accept-Encoding: gzip<br>-   BereqHeader    X-defHash: /event/diff?id=707658&rev=925&country=ES&LANG=en&xfarm=2 + <a href="http://www.xxx.ge">www.xxx.ge</a><br>-   BereqHeader    X-Varnish: 721019<br>-   VCL_call       BACKEND_FETCH<br>-   VCL_return     fetch<br>-   BackendOpen    28 boot.wb2_mob_stx_spo_gr 172.16.50.132 80 172.16.50.80 48508<br>-   BackendStart   192.168.50.132 80<br>-   Timestamp      Bereq: 1468531337.961247 0.000078 0.000078<br>-   Timestamp      Beresp: 1468531337.963066 0.001897 0.001819<br>-   BerespProtocol HTTP/1.1<br>-   BerespStatus   304<br>-   BerespReason   Not Modified<br>-   BerespHeader   Cache-Control: private<br>-   BerespHeader   Server: Microsoft-IIS/8.5<br>-   BerespHeader   Set-Cookie: LANG=en; expires=Fri, 14-Jul-2017 21:22:17 GMT; path=/; secure; HttpOnly<br>-   BerespHeader   X-AspNetMvc-Version: 5.2<br>-   BerespHeader   X-AspNet-Version: 4.0.30319<br>-   BerespHeader   X-Powered-By: <a href="http://ASP.NET">ASP.NET</a><br>-   BerespHeader   X-Farm: 12<br>-   BerespHeader   Date: Thu, 14 Jul 2016 21:22:17 GMT<br>-   TTL            RFC 120 10 -1 1468531338 1468531338 1468531337 0 0<br>-   Error          304 response but not conditional fetch<br>-   BackendClose   28 boot.wb2_mob_stx_spo_gr<br>-   BereqAcct      574 0 574 293 0 293<br>-   End<br></div>