Browser waits forever to load page. How do I tell what's causing the delay?

I'm experiencing long page load times on my local development environment. Page loads time of up to 25 minutes. As far as I can tell, the browser is not waiting for the server to respond but waiting for some http request that is being kept alive by something. If I run a php script that times out, the response is immediate so I know it's not my scripts that are taking forever (and firebug confirms this). I suspect my local site is trying to connect to a third party that won't respond. It doesn't matter what browser I use, the behaviour is the same.

My questions are:

How can I tell what is taking a long time? Firebug tells me nothing.

What do I look for in the http headers that tells whatever is making the request to wait forever?

How can I get the site to fail early and feed back to me what is causing the delay?

Can I watch the requests i开发者_StackOverflow社区n real time?

Any help is much appreciated.

you could install a proxy level debugging tool, like Fiddler, and watch all of your http traffic go by.

otherwise, you're deep into networking diagnostics stuff?

What does Firebug or Chrome developer tools have to say? Look in the "Net" or "Network" sections respectively. They should be able to break down exactly what is or is not loading and when.

You can also get down in the weeds using Speed Tracer if you want to see low level stuff like JS parsing or DOM events.