Virtual Hosting is where you have multiple sites on a single IP address, and the web server determines which site you’re requesting based on the name that you’ve typed into your browser. More precisely it looks at the Host header sent in the request.

If the DNS isn’t set up for your site yet then you’re normally unable to test it as you can’t just enter the IP address, because then the server doesn’t get the name so can’t match the request to a site.

Charles can help solve this problem with its Spoof DNS tool.