Virtual Hosting and its types

Apache is a very powerful web server, highly flexible and configurable Web server for Nix OS As we all are aware that. we are going to discuss feature of Apache which allows us to host more than one website on a single Linux machinery. Implementing virtual hosting with a  Apache web server can help you to save costs you are investing on your server maintenance and their administration. Concept of Shared web hosting and Reseller web hosting is based on this facility of Apache only.

It is a kind of hosting that helps in hosting of multiple domain names on a single server based technology. This help ones 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 being used to refer to web servers but its principles involves other internet services aswell.

TYPES OF VIRTUAL HOSTS

1) Name Based Virtual Hosting:

With the name based virtual hosting you can host severaldomains/websites on a single machine with a single ip address. All domain on that server will be sharing a single IP address. It is easier to configured than the  IP based virtual hosting, you should only need to configure DNS of the domain to map it with its correct IP address and then configure Apache to recognize it with the domain names.

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 address and the associated administrative overhead but the protocol that is being served must supply valid host name at an appropriated point.

There are some difficulties while using name-based virtual hosting with SSL and TLS as, it becomes very difficult to host multiple secure website that runs SSL and TLS because their handshakes takes place even before the expected hostname is sent to the server, the server is unabled to detect that  what kind of certificate is to presented in the handshake.

Moreover if the Domain Name System(DNS) is not functioning properly, it becomes difficult to access virtually-hosted website even if the IP address is known.

2) IP Based Virtual Hosting:

With the IP based Virtual hosting, you can be able assign a separate IP for the each domain on a single server side, these IP addresses can be attached to the server with single NIC cards and as well as multiple NICs. Port-based virtual hosting is also possible in its principle but it is rarely used in practice as it is unfriendly to  users. By default the port number for HTTP is 80.

Name-based  and IP-based virtual hostings can be combined that means a server can have multiple IP addresses that serves multiple names on some or all of the IP addresses.