Nginx hang and do not respond with large number of network connection in FIN_WAIT state

[Peter Booth]

Is your nginx/Apache site visible on the internet without any authentication?

If so, I recommend that you access your site directly, not through cloud flare with redbot.org, which is the best HTTP debugger ever, for both the nginx and Apache versions of the site and see how they compare.

Why isn’t your root page / being served from your CDN edge? Is the cloudfkare configured to not cache /?
If so, why?

Sent from my iPhone

> On Jan 10, 2019, at 11:32 PM, gnusys <nginx-forum at forum.nginx.org> wrote:
> 
> The TCP state graph for the situation is:
> 
> https://i.imgur.com/USECPtc.png
> 
> You can see at 16:55 the FIN_WAIT1 ,CLOSE_WAIT and ESTABLISHED takes a steep
> climb, At this point Nginx hangs as the server has a script that checks stub
> status and this doesn't finish. The server itself and all other services
> like sshd works pretty fine ,except Nginx 
> 
> At 17:06 you can see the connection states drop steeply too. this is the
> point where Nginx is stopped and Apache takes over as the webserver 
> The ESTABLISHED and CLOSE_WAIT drop fully and the FIN_WAIT1 reduces slowly
> and finally attain normalcy at 17:15
> 
> Apache continued working fine with the same amount of external traffic and
> same firewall setup
> 
> Posted at Nginx Forum: https://forum.nginx.org/read.php?2,282613,282650#msg-282650
> 
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