I have a HTTP proxy running at localhost:1234. The proxy works fine for all web requests I make.
I have a server running at localhost:4567 . I want HTTP requests to my server to go through my proxy. Should be simple, right? Is there a way to make IE or any other browser do this?
Generally you can configure your browser settings for this. In Firefox it's Options -> Advanced -> Network -> Connection (Settings).
IE automatically ignores proxies if it detects a localhost URL. This has always been a thorn in the side of tools like Fiddler.
However, you can often get around that by literally going to http://somesite.com:1234. Someone has taken the time to register the "somesite.com" domain to automatically route to 127.0.0.1. This fools IE into thinking it's an outside domain, but should run through your proxy while redirecting to your local server.
Good luck.
It depends on your browser. In Firefox, check to see that "no proxy" is empty. By default Firefox blocks proxy of URLs to localhost and 127.0.0.1.