title: recv() failed (104: Connection reset by peer) while waiting for request, client: 100.109.209.0, server: 0.0.0.0:80
body: <p>I have one confusion about the nginx logs as below, it occurs very frequently, I am not sure if this has some potential issue or not. </p>
  
  <p>nginx and php-fpm versions:</p>
  
  <pre><code>nginx version: nginx/1.6.3
  
  PHP 7.0.11 (fpm-fcgi) (built: Sep 17 2016 12:55:16)
  Copyright (c) 1997-2016 The PHP Group
  Zend Engine v3.0.0, Copyright (c) 1998-2016 Zend Technologies
      with Zend OPcache v7.0.11, Copyright (c) 1999-2016, by Zend Technologies
  </code></pre>
  
  <p>nginx debug logs:</p>
  
  <pre><code>2016/10/17 17:15:07 [info] 7047#0: *620 recv() failed (104: Connection reset by peer) while waiting for request, client: 100.109.209.0, server: 0.0.0.0:80
  2016/10/17 17:15:07 [debug] 7047#0: *620 close http connection: 28
  2016/10/17 17:15:07 [debug] 7047#0: *620 event timer del: 28: 1476695767331
  2016/10/17 17:15:07 [debug] 7047#0: *620 reusable connection: 0
  2016/10/17 17:15:07 [debug] 7047#0: *620 free: 0000000001C3BAE0
  2016/10/17 17:15:07 [debug] 7047#0: *620 free: 0000000001CB9330, unused: 0
  2016/10/17 17:15:07 [debug] 7047#0: *620 free: 0000000001CB9440, unused: 120
  2016/10/17 17:15:07 [debug] 7047#0: posted event 0000000000000000
  2016/10/17 17:15:07 [debug] 7047#0: worker cycle
  2016/10/17 17:15:07 [debug] 7047#0: accept mutex locked
  2016/10/17 17:15:07 [debug] 7047#0: epoll timer: 40915
  2016/10/17 17:15:07 [debug] 7048#0: timer delta: 501
  2016/10/17 17:15:07 [debug] 7048#0: posted events 0000000000000000
  2016/10/17 17:15:07 [debug] 7048#0: worker cycle
  2016/10/17 17:15:07 [debug] 7048#0: accept mutex lock failed: 0
  2016/10/17 17:15:07 [debug] 7048#0: epoll timer: 500
  2016/10/17 17:15:07 [debug] 7047#0: epoll: fd:10 ev:0001 d:00007F32B02DE010
  2016/10/17 17:15:07 [debug] 7047#0: post event 00007F32AFC5E010
  2016/10/17 17:15:07 [debug] 7047#0: timer delta: 46
  2016/10/17 17:15:07 [debug] 7047#0: posted event 00007F32AFC5E010
  2016/10/17 17:15:07 [debug] 7047#0: delete posted event 00007F32AFC5E010
  2016/10/17 17:15:07 [debug] 7047#0: accept on 0.0.0.0:80, ready: 0
  2016/10/17 17:15:07 [debug] 7047#0: posix_memalign: 0000000001CB9330:256 @16
  2016/10/17 17:15:07 [debug] 7047#0: *621 accept: 100.109.210.0 fd:28
  2016/10/17 17:15:07 [debug] 7047#0: posix_memalign: 0000000001CB9440:256 @16
  2016/10/17 17:15:07 [debug] 7047#0: *621 event timer add: 28: 60000:1476695767377
  2016/10/17 17:15:07 [debug] 7047#0: *621 reusable connection: 1
  2016/10/17 17:15:07 [debug] 7047#0: *621 epoll add event: fd:28 op:1 ev:80002001
  2016/10/17 17:15:07 [debug] 7047#0: posted event 0000000000000000
  2016/10/17 17:15:07 [debug] 7047#0: posted events 0000000000000000
  2016/10/17 17:15:07 [debug] 7047#0: worker cycle
  2016/10/17 17:15:07 [debug] 7047#0: accept mutex locked
  2016/10/17 17:15:07 [debug] 7047#0: epoll timer: 40869
  2016/10/17 17:15:07 [debug] 7047#0: epoll: fd:28 ev:2019 d:00007F32B02DEBE0
  2016/10/17 17:15:07 [debug] 7047#0: epoll_wait() error on fd:28 ev:2019
  2016/10/17 17:15:07 [debug] 7047#0: *621 post event 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: timer delta: 0
  2016/10/17 17:15:07 [debug] 7047#0: posted events 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: posted event 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: *621 delete posted event 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: *621 http wait request handler
  2016/10/17 17:15:07 [debug] 7047#0: *621 malloc: 0000000001C3BAE0:16384
  2016/10/17 17:15:07 [debug] 7047#0: *621 recv: fd:28 -1 of 16384
  2016/10/17 17:15:07 [info] 7047#0: *621 recv() failed (104: Connection reset by peer) while waiting for request, client: 100.109.210.0, server: 0.0.0.0:80
  2016/10/17 17:15:07 [debug] 7047#0: *621 close http connection: 28
  2016/10/17 17:15:07 [debug] 7047#0: *621 event timer del: 28: 1476695767377
  2016/10/17 17:15:07 [debug] 7047#0: *621 reusable connection: 0
  2016/10/17 17:15:07 [debug] 7047#0: *621 free: 0000000001C3BAE0
  2016/10/17 17:15:07 [debug] 7047#0: *621 free: 0000000001CB9330, unused: 0
  2016/10/17 17:15:07 [debug] 7047#0: *621 free: 0000000001CB9440, unused: 120
  2016/10/17 17:15:07 [debug] 7047#0: posted event 0000000000000000
  2016/10/17 17:15:07 [debug] 7047#0: worker cycle
  2016/10/17 17:15:07 [debug] 7047#0: accept mutex locked
  2016/10/17 17:15:07 [debug] 7047#0: epoll timer: 40869
  2016/10/17 17:15:07 [debug] 7047#0: epoll: fd:10 ev:0001 d:00007F32B02DE010
  2016/10/17 17:15:07 [debug] 7047#0: post event 00007F32AFC5E010
  2016/10/17 17:15:07 [debug] 7047#0: timer delta: 44
  2016/10/17 17:15:07 [debug] 7047#0: posted event 00007F32AFC5E010
  2016/10/17 17:15:07 [debug] 7047#0: delete posted event 00007F32AFC5E010
  2016/10/17 17:15:07 [debug] 7047#0: accept on 0.0.0.0:80, ready: 0
  2016/10/17 17:15:07 [debug] 7047#0: posix_memalign: 0000000001CB9330:256 @16
  2016/10/17 17:15:07 [debug] 7047#0: *622 accept: 100.109.211.0 fd:28
  2016/10/17 17:15:07 [debug] 7047#0: posix_memalign: 0000000001CB9440:256 @16
  2016/10/17 17:15:07 [debug] 7047#0: *622 event timer add: 28: 60000:1476695767421
  2016/10/17 17:15:07 [debug] 7047#0: *622 reusable connection: 1
  2016/10/17 17:15:07 [debug] 7047#0: *622 epoll add event: fd:28 op:1 ev:80002001
  2016/10/17 17:15:07 [debug] 7047#0: posted event 0000000000000000
  2016/10/17 17:15:07 [debug] 7047#0: posted events 0000000000000000
  2016/10/17 17:15:07 [debug] 7047#0: worker cycle
  2016/10/17 17:15:07 [debug] 7047#0: accept mutex locked
  2016/10/17 17:15:07 [debug] 7047#0: epoll timer: 40825
  2016/10/17 17:15:07 [debug] 7047#0: epoll: fd:28 ev:2019 d:00007F32B02DEBE1
  2016/10/17 17:15:07 [debug] 7047#0: epoll_wait() error on fd:28 ev:2019
  2016/10/17 17:15:07 [debug] 7047#0: *622 post event 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: timer delta: 0
  2016/10/17 17:15:07 [debug] 7047#0: posted events 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: posted event 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: *622 delete posted event 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: *622 http wait request handler
  2016/10/17 17:15:07 [debug] 7047#0: *622 malloc: 0000000001C3BAE0:16384
  2016/10/17 17:15:07 [debug] 7047#0: *622 recv: fd:28 -1 of 16384
  2016/10/17 17:15:07 [info] 7047#0: *622 recv() failed (104: Connection reset by peer) while waiting for request, client: 100.109.211.0, server: 0.0.0.0:80
  2016/10/17 17:15:07 [debug] 7047#0: *622 close http connection: 28
  2016/10/17 17:15:07 [debug] 7047#0: *622 event timer del: 28: 1476695767421
  2016/10/17 17:15:07 [debug] 7047#0: *622 reusable connection: 0
  2016/10/17 17:15:07 [debug] 7047#0: *622 free: 0000000001C3BAE0
  2016/10/17 17:15:07 [debug] 7047#0: *622 free: 0000000001CB9330, unused: 0
  2016/10/17 17:15:07 [debug] 7047#0: *622 free: 0000000001CB9440, unused: 120
  2016/10/17 17:15:07 [debug] 7047#0: posted event 0000000000000000
  2016/10/17 17:15:07 [debug] 7047#0: worker cycle
  2016/10/17 17:15:07 [debug] 7047#0: accept mutex locked
  2016/10/17 17:15:07 [debug] 7047#0: epoll timer: 40825
  2016/10/17 17:15:07 [debug] 7047#0: epoll: fd:10 ev:0001 d:00007F32B02DE010
  2016/10/17 17:15:07 [debug] 7047#0: post event 00007F32AFC5E010
  2016/10/17 17:15:07 [debug] 7047#0: timer delta: 36
  2016/10/17 17:15:07 [debug] 7047#0: posted event 00007F32AFC5E010
  2016/10/17 17:15:07 [debug] 7047#0: delete posted event 00007F32AFC5E010
  2016/10/17 17:15:07 [debug] 7047#0: accept on 0.0.0.0:80, ready: 0
  2016/10/17 17:15:07 [debug] 7047#0: posix_memalign: 0000000001CB9330:256 @16
  2016/10/17 17:15:07 [debug] 7047#0: *623 accept: 100.109.216.0 fd:28
  2016/10/17 17:15:07 [debug] 7047#0: posix_memalign: 0000000001CB9440:256 @16
  2016/10/17 17:15:07 [debug] 7047#0: *623 event timer add: 28: 60000:1476695767457
  2016/10/17 17:15:07 [debug] 7047#0: *623 reusable connection: 1
  2016/10/17 17:15:07 [debug] 7047#0: *623 epoll add event: fd:28 op:1 ev:80002001
  2016/10/17 17:15:07 [debug] 7047#0: posted event 0000000000000000
  2016/10/17 17:15:07 [debug] 7047#0: posted events 0000000000000000
  2016/10/17 17:15:07 [debug] 7047#0: worker cycle
  2016/10/17 17:15:07 [debug] 7047#0: accept mutex locked
  2016/10/17 17:15:07 [debug] 7047#0: epoll timer: 40789
  2016/10/17 17:15:07 [debug] 7047#0: epoll: fd:28 ev:2019 d:00007F32B02DEBE0
  2016/10/17 17:15:07 [debug] 7047#0: epoll_wait() error on fd:28 ev:2019
  2016/10/17 17:15:07 [debug] 7047#0: *623 post event 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: timer delta: 1
  2016/10/17 17:15:07 [debug] 7047#0: posted events 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: posted event 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: *623 delete posted event 00007F32AFC5E5C0
  2016/10/17 17:15:07 [debug] 7047#0: *623 http wait request handler
  2016/10/17 17:15:07 [debug] 7047#0: *623 malloc: 0000000001C3BAE0:16384
  2016/10/17 17:15:07 [debug] 7047#0: *623 recv: fd:28 -1 of 16384
  2016/10/17 17:15:07 [info] 7047#0: *623 recv() failed (104: Connection reset by peer) while waiting for request, client: 100.109.216.0, server: 0.0.0.0:80
  </code></pre>
  
  <p>Nginx and php-fpm config is default. 
  My develop environment the same config, does not exist the issue. Why? How to fix it?</p>