Nginx reverse proxy – doesn’t close upstream connection when HTTPS client disconnects

httpsnginx

I have a server which needs to know when the client closes the connection. The server is behind an nginx reverse proxy. Everything works fine over HTTP, but as soon as I turn SSL on, nginx seems to hold the upstream connection open for a full minute after the HTTPS client has disconnected.

How can I get nginx to close the upstream connection when the client disconnects?

Here's my nginx config:

ssl_session_cache off;
server {
  listen 443;
  ssl on;
  ssl_certificate server.crt;
  ssl_certificate_key server.key;
  location /find {
    proxy_pass http://my_upstream;
    proxy_ignore_client_abort off;
    proxy_buffering off;
  }
}

Best Answer

Quite late but might be helpful for others. I had the same problem and it turned out to be an issue with nginx (see https://www.ruby-forum.com/topic/4412004):

So the underlying problem is that the nginx stream layer abstraction isn't clean enough to handle low level OS events and then map them through the SSL layer to read/write/eof conceptual events as needed. Instead you need an OS level "eof" event, which you then assume maps through the SSL abstraction layer to a SSL stream eof event.

Ok, so I had a look at the kqueue eof handling, and what's needed for epoll eof handling, and created a quick patch that seems to work.

I applied the patch on 1.4.2 and it worked! No problems so far. Hopefully it will be fixed in one of the next releases.

Edited

This problem seems to be solved with nginx version >=1.5.5:

Feature: now nginx uses EPOLLRDHUP events to detect premature connection close by clients if the "epoll" method is used.

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