Virtual Hosting- An easy way to host multiple domain names
It is a kind of hosting that helps in hosting of multiple domain names on a single server. This helps one server to share their resources like memory and processor cycles without the requirement of all services provided to use the same name of the host.
Basically, the virtual hosting is used to refer to web servers but its principles involves other internet services as well.
There are two main types of virtual hosting:
Name-based and IP-based.
Where Name-based virtual hosting can make the use of multiple host names for the same IP address and also it uses the host name that is presented by the client. This helps in saving the IP addresses and the associated administrative overhead but the protocol that is being served must supply valid host name at an appropriate point. There are some difficulties in using name-based virtual hosting with SSL/TLS as, it becomes difficult to host multiple secure websites that runs SSL/TLS because their handshakes takes place even before the expected hostname is sent to the server, the server is unable to detect what kind of certificate is to presented in the handshake.
Moreover, if the Domain Name System is not functioning properly, it becomes difficult to access virtually-hosted website even if the IP address is known.
On the other side IP-based virtual hosting makes the use of separate IP address for each of the host name that means each site points out to a unique IP address, and it can be performed with any protocol as it just requires a dedicated IP address per domain name served.
Port-based virtual hosting is also possible in its principle but it is rarely used in practice as it is unfriendly to the users. By default, port number for HTTP is 80.
Name-based as well as IP-based virtual hosting can be combined that means a server can have multiple IP addresses that serves multiple names on some or all of the IP addresses.
Virtual web hosting is used on a large scale bases in the companies whose business model helps in providing a low cost website hosting for their customers. The vast majority of the websites worldwide are hosted on shared servers, that uses the virtual hosting technology.