What you want can be achieved by modifying the hosts file through Fiddler 2 application.

Follow these steps:

        Install Fiddler2
        Navigate to Fiddler2 menu:- Tools > HOSTS.. (Click to select)

        Add a line like this:-

        localhost:8080        www.mydomainname.com
        Save the file & then checkout www.mydomainname.com in browser.