Testing PWS is very easy: Start your browser In the Location/Address bar, type in either "http://localhost" or "http://127.0.0.1". You will be brought to a welcome page. The IP address of 127.0.0.1 is known as a loop back address. It is always the default web IP address for the machine that the server is running on. "localhost" is the domain name assigned to the loop back IP address.