Sites that are hosted via a shared hosting program, though they physically reside on the same server, appear to be on different machines to the outside world. There are two main ways in which this is accomplished.
Some sites have separate IP addresses. For surfers, there is no appreciable difference between visiting sites hosted on separate servers and sites hosted on a shared server when those sites are located at different IP addresses. The sites are “unaware” of one another as are the users who visit them. The capability to provide this sort of site separation without the requirement of their being two separate machines is what makes web hosting affordable. Web hosting companies can host many small sites on one server, cutting their expenses and, thus, their customer’s prices.
Some sites are hosted at the same IP address and separated only by name. This is a fairly common arrangement for users that own several domain names and host them with the same company. The site’s domain name is assigned to the directory that holds that site’s files. When a user visits the IP address, the site name serves as the means by which the server decides which directory the user should be offered. This is usually set up by the web hosting company and, for the user, is only as complicated as uploading files to the appropriate directory.
Either way, sites on shared hosts appear to reside on different servers to outside users