The Domain Name System is an Internet naming system that makes it possible to assign domain names to groups of Internet resources and users, independent of each entity’s physical location. Domain names are easier to remember than IP addresses such as 207.75.188.166 (IPv4) or 2001:db6:1f70::999:de8:7648:6e8 (IPv6). Internet users use domain names to recite meaningful Uniform Resource Locators (URLs) and e-mail addresses.

The Domain Name System distributes the responsibility of assigning domain names and mapping those names to IP addresses by designating name servers for each domain. Name servers are responsible for their particular domains. The are DNS distributed and fault tolerant. This makes possible for the WWW to avoid keeping everything in a single central register which has to be continually consulted and updated.

Domain Name System also stores information about the list of mail servers that accept email for web addresses. Domain Name System is a very important component of the Internet as we know it because it provides a distributed keyword-based redirection service.

Colocation is a term used to describe a certain type of IT Hosting service provided by telecommunication facilities and data centers to clients who own equipment and need to house it. There are different levels of Colocation – from colocation of a single standard desktop computer or rack server to rack enclosures (cabinets) used for colocation of multiple computing appliances.

The minimum services provided by the host facility (data center) to a client are: space, power feed, access to internet service, power and cooling. The facilities usually house IT equipment into rack cabinets (See “Server Cabinet”, “19-inch Rack” and “Tower Server Rack”), mount them into rack units, connect them to special types of power distribution units (PDU) and connect them to networking equipment (network switches) to provide them with Internet connectivity.