In a WinForms or Console application using the default proxy settings works just fine and Fiddler as well as other Http proxies like Charles automatically pick up the .NET Web Service/Http requests as they run through the Windows HTTP pipeline.
IIS7 HAS CHANGED DEFAULT SITUATION
Fiddler or Charles no longer work directly on Web Service or straight HTTP calls using WebRequest/WebClient and if you’re expecting to debug a Web Service/Http request you get Nada in these Http debuggers.
explicitly specify the proxy settings in web.config:
<system.net> <defaultProxy> <proxy proxyaddress="http://127.0.0.1:8888" /> </defaultProxy> </system.net>
You specify the proxy IP address and port as an Http Uri. These settings above are set for the default settings that Fiddler uses since both ASP.NET and Web Services Clients and Http Clients all access the system.net settings from the configuration.
Applying these settings will make HttpWebRequest, WebClient and WCF or Web Service requests (as long as they’re using default ports) pick up the outbound requests and display Http request information.
If you run Https requests through these types of proxies you’ll need to add the specific certificates that Fiddler and Charles install to your personal trusted certificate store. If you don’t do this the requests will fail to invalid certificate errors.