Sometimes you want to test a domain name as if it pointed to a different IP address. For example, if you have set up a virtual host but the IP address change hasn’t propagated through DNS yet, you can spoof it and test your virtual hosting immediately.

Charles contains a list of domain name to ip address mappings which you configure. When a request comes in for a listed domain name, the Spoof DNS plugin finds the spoof IP redirects the request to that address. The Host HTTP-header remains intact, so it is exactly as if your DNS server returned the spoofed IP.