Monitor traffic to localhost from IE or .NET

To monitor traffic sent to http://localhost or from IE8 or below or the .NET Framework:

  • Use your machine name as the hostname instead of Localhost or

    For example, instead of


    Go to:

  • Use one of these addresses:

    -To use the IPv4 adapter (recommended for the Visual Studio test webserver, codename: Cassini):


    -To use the IPv6 adapter:


    -To use localhost in the Host header:

  • Click Rules > Customize Rules... and add this code to the Rules file:

    static function OnBeforeRequest(oSession:Fiddler.Session){
    if (oSession.HostnameIs("MYAPP")) { = ""; }

    Now, http://myapp will act as an alias for

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