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By default, Apache2 seems to allow only 1 connection per IP address.

How do I configure Apache2 to allow multiple simultaneous connections from the same IP address?

Here is my situation:

  1. a web app being hosted on a server.
  2. a remote client makes an request that may take 15 seconds to complete.
  3. the same remote client makes another (independent) request.
  4. at present, the 2nd request sits in a queue until the 1st request completes, since Apache2 seems to impose a limit of 1 connection per IP address.

How do I override this default behaviour and allow the 2nd request to be processed in parallel?

thanks in advance, David Jones

David Jones
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  • what platform are you running Apache2 on? – Fosco Aug 17 '10 at 20:22
  • Have you checked out mod_limitipconn module? - http://dominia.org/djao/limitipconn2.html – Adam Aug 17 '10 at 20:29
  • definitely weird behavior you're seeing since this doesn't normally happen. did you do anything odd with the config? – NG. Aug 17 '10 at 20:30
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    The problem that the original poster had was not related to apache at all, but PHP sessions. Nevertheless, I suggest that the title and post not be modified, because other readers might have the same misunderstanding and this helps them find the right answer. – cornergraf Aug 13 '14 at 05:48
  • Agree with @cornergraf on keeping the title. I found this post because I was searching for Apache and now know its a PHP issue. – Justin Khoo Jan 19 '20 at 20:52

1 Answers1

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I discovered the answer to my problem. It turns out others have encountered this difficulty before:

Simultaneous Requests to PHP Script

The key detail is that file-based sessions in PHP cause all requests from the same client to be processed sequentially in a queue, rather than in parallel.

In order to solve this problem, it is necessary to make a call to session_write_close() in every PHP script as soon as session handling is finished.

-- David Jones

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David Jones
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    Thanks for this question and answer - it helped me alot. BTW - I verified the file-based sessions are the cause of the problem by testing first 2 tabs in the same browser (shared session), then with 1 tab in 2 different browsers (different sessions). – Tom Oct 31 '13 at 18:26