Monitor traffic to localhost from IE or .NET

To monitor traffic sent to http://localhost or http://127.0.0.1 from IE8 or below or the .NET Framework:

  • Use your machine name as the hostname instead of Localhost or 127.0.0.1

    For example, instead of

    http://localhost:8081/mytestpage.aspx
    

    Go to:

    http://machinename:8081/mytestpage.aspx
    
  • Use one of these addresses:

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

    http://ipv4.fiddler
    

    -To use the IPv6 adapter:

    http://ipv6.fiddler
    

    -To use localhost in the Host header:

    http://localhost.fiddler
    
  • Click Rules > Customize Rules... and add this code to the Rules file:

    static function OnBeforeRequest(oSession:Fiddler.Session){
    if (oSession.HostnameIs("MYAPP")) { oSession.host = "127.0.0.1:8081"; }
    }
    

    Now, http://myapp will act as an alias for 127.0.0.1:8081