How can I test/debug my VB.NET app with a proxy server?

I have a small desktop Twitter client written in VB.NET (2.0). Works great. Some of my users have emailed me and said that the application isn't working for them because they are trying to use it on networks where a proxy server is part of the network connectivity equation.

I'd like to be able to troubleshoot and debug my application at home so that I can add proxy au开发者_如何学运维thentication to my application as a feature.

Are there software proxies that I can install on my local machine for this sort of thing? Free/open-source is preferable, since this is a FOSS project. Failing that, are there other alternatives that I could use for this sort of troubleshooting/debugging/development?

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How about using Charles HTTP Debugger to run your tests. Basically, fireup Charles, run your app, and test. Charles is the man in the middle and acts as a proxy and also logs ALL HTTP traffic from your machine. Let me know if that helps.

http://www.charlesproxy.com/