Unable to connect -- possible Apache2 problem

It seems unlikely that this would be a client limit issue with Apache since clicking in the same client browser should either reuse an existing connection or have torn an old one down if it is making a new one. Are you the only client to the box during the tests? If so, the default listen backlog of Apache should make it even less likely that it's a client limit issue, unless each thing you're clicking on is taking a very long time to respond.

I assume you're having Apache proxy the request to trac? When you get a connection refused by the client, is there any related log at all in the Apache logs or the trac log? If not, then the blockage would seem to be likely upstream of them and outside of their control.

Just for the heck of it - any chance you have any rate limiting going on in a firewall configuration? Maybe your rapid clicking is exceeding the rate limit and the delay then lets the average rate fall beneath the threshold. Though if so it sounds like you may have some pretty low limits.

If unsure, one test is just to temporarily disable any firewall you may have and see if the behavior changes. I might also test from different client locations in case what you're seeing is client side (some bad or limiting behavior in a local nat box or something).

– David

Thank you! You were right. It wasn't apache after all. It was my firewall and its rate limiting was the culprit.