Nginx behind a reverse proxy sending 499

[Maxim Dounin]

Hello!

On Sun, Jan 11, 2015 at 01:37:31AM -0500, ppwm wrote:

> To debug the issue further, I wrote a simple Java based HTTP client. This
> client would open a socket to the nginx server, write the request line (GET
> / HTTP/1.1), write the host header, write the Connection:close header and
> commit the request. While committing the write the CRLF character twice.
> 
> In this setup, I tested by having a proxy pass to www.google.com and not
> having a proxy pass (nginx servers the default index.html.
> 
> If there is no proxy pass, nginx never gives a 499 status code. Even if I do
> Socket.shutdownOutput(), nginx give a valid 200 response. This is
> irrespective of the Connection header (keepalive/close).
> 
> If there is proxy pass,  I get a valid response if I don't do
> Socket.shutdownOutput(). But if I do Socket.shutdownOutput(), I get 499
> irrespective of Connection header (keepalive/close). This implies that nginx
> is treating client's Socket.shutdownOutput() as client closing the
> connection despite all data being written to the socket.

In HTTP, it's generally a bad idea to shutdown the socket before 
you've got the response.  While not strictly prohibited, the 
server will likely think that the client bored waiting for a 
response and closed the connection, so there is no need to return 
any response.  Google for something like "http tcp half-close" for 
more details.

The "proxy_ignore_client_abort" directive can be used if you want 
nginx to be compatible with such clients for some reason, see 
here:

http://nginx.org/r/proxy_ignore_client_abort

-- 
Maxim Dounin
http://nginx.org/