Difference between ie proxy settings and winhttp proxy settings [closed]

What is the difference between the proxy settings that we set in IE vs. the settings that we could do using netsh winhttp

Who uses which settings? In particular, which one does IIS use by default.

You can configure proxy settings for IIS in the web.config. http://msdn.microsoft.com/en-us/library/kd3cf2ex.aspx

Since the proxy configuration in web.config references System.Net, I assume that IIS uses winhttp when retrieving proxy settings.

One thing to note is that winttp can retrieve settings from IE or try to autodetect proxy settings via. web proxy auto detect (WPAD). When faced with winhttp proxy issues you can use the following command to set winhttp to the IE proxy settings. netsh winhttp>import proxy source=ie

My experience is that windows uses winhttp for certain services, for example when downloading windows updates and performing certification revocations checks.