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From André Warnier>
Subject Re: [users@httpd] ProxyTimeout
Date Wed, 19 Aug 2009 21:00:26 GMT
Qingshan Xie wrote:
> Thanks for your quick reply. 
> I am wondering what will happen in the case below, 
>            Timeout             ProxyTimout
> browser <===========> proxy <===============> backend
>  Timeout = 300 sec and ProxyTimeout = 600 sec, 
> If backend process longer than 5 min, what will happen?  
>>>From the observation of my server,  the whole HTTP session won't be terminated
till 10 min.  I am not sure why since the front connection should be terminated in 5 min?
I am not entirely sure, since I have not examined the Apache code 
itself, but in my understanding, the "Timeout" parameter, precisely and 
only, applies when Apache is waiting for something from the browser, and 
the browser is not sending it.
For example :
- the browser creates a TCP connection to the Apache server, on port 80.
- Apache accepts this TCP connection
- Apache now waits for the browser to send a request over that connection
- the browser, for whatever reason, is not sending the request (or not a 
complete request), within "Timeout" seconds

Then the Timeout applies.  Apache will close the connection, because it 
is not getting the expected request over that connection.
This avoids a kind of DOS attack, whereby clients could open many 
connections to Apache, then not send any request, blocking Apache forever.

So it does /not/ apply when it is Apache that should send something to 
the browser, and does not send it.  In that last case, what may happen 
is that /the browser/ times out, because Apache takes too long to 
respond.  In my experience, this browser timeout is several minutes 
(3..5 ?).  I don't know if this timeout is adjustable in the usual browsers.

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