VPS Hosting is known as Virtual Private Server,and it is an Virtualized server.Technically it is called as both Shared hosting and dedicated hosting.VPS Hosting is work similar to VMware.This allow you to run several virtualized operating systems on one machine. For example, your desktop may be running Windows 7, but you can also run other operating systems such as Windows XP or Linux without needing to restart your computer. There are two main types of virtual hosting, name-based and IP-based. Name-based virtual hosting uses the host name presented by the client. This saves IP addresses and the associated administrative overhead but the protocol being served must supply the host name at an appropriate point. In particular, there are significant difficulties using name-based virtual hosting with SSL/TLS. IP-based virtual hosting uses a separate IP address for each host name, and it can be performed with any protocol but requires a dedicated IP address per domain name served. Port-based virtual hosting is also possible in principle but is rarely used in practice because it is unfriendly to users. Name-based and IP-based virtual hosting can be combined: a server may have multiple IP addresses and serve multiple names on some or all of those IP addresses. This technique can be useful when using SSL/TLS with wildcard certificates. For example, if a server operator had two certificates, one for *.example.com and one for *.example.net, he could serve foo.example.com and bar.example.com off the same IP address but would need a separate IP address for baz.example.net.