A domain name service, or Domain Name System (DNS), is a hierarchical system to associate a name of a server with its absolute numerical Internet Protocol (IP) address. DNS servers translate, for example, the name www.website.com into its unique numeric address on the Internet. IP addresses are numerical. Their format is something like 64.231.33.12. Although the server is accessible via the numeric address, the language domain name is easier for people to remember.
History
The first Request for Comments (RFC) for DNS service was written in 1983. RFC 882 was written in response to the rapid growth of servers and hosts. In 1984, RFC 920 defined top-level domains like .com, .gov, .net and .org. In 1997, the DNS policy of generic top-level domains was accepted. Generic top-level domains allow for national top-level domains and less-used top-level domains like .name or .info.
Registering a Domain Name
Early domain names were registered via a central service called InterNIC. InterNIC was assigned to the Internet Corporation of Assigned Names and Numbers (ICANN). As demand for domain names outstripped the ability of ICANN to deliver, InterNIC was transferred to a private company, Network Solutions. After some time, domain registration was opened up to a number of different companies. At present, to register a domain name one of many domain name registration services is authorized to associate a name with an IP and submit that name to the network of DNS servers.
DNS Servers
DNS servers are the servers where the natural language names of websites and servers are associated with the numeric server addresses. DNS servers are populated from a central source of new domain registrations. Web hosting companies normally have a mirror of that central server or a secondary server. In some cases, it can take several days for the new DNS records to populate servers below the central DNS server architecture.
Most Internet Service Providers (ISPs) offer internal DNS servers to make domain name look-up faster. However, there are a number of public DNS servers, including servers provided by Google, Level 3 and Verizon. Public DNS servers are especially useful when your local DNS servers have problems or fail.
Reverse Look-ups
In some cases, someone may need to learn the owner or contact information of a particular domain name. By looking up the registration record for a domain name, you can sometimes find the name, address and phone number of the owner. However, some registrars offer a service that makes domain names anonymous. These services list the domain registrar as the contact point. The registrar will forward emails to your registered email address, thus protecting your privacy.
Significance
DNS servers have allowed people to associate memorable natural language names with websites. For example, without DNS, Amazon.com would be 72.21.207.65. If Amazon decided to use a different front-end server with a different address, you would no longer be able to access the site because of the change in numerical address. However, DNS will point all requests for Amazon.com to the new numerical address. As the world runs out of available IP addresses, a new version of IP addressing has been developed. As IPv6 is implemented to replace the current IPv4, it is likely to be a simple job to add a v6 address to the DNS system.