What is a Domain Name?

What is a Domain Name?
Domain names are used to identify one or more IP addresses. For example, the domain name microsoft.com represents about a dozen IP addresses. Domain names are used in URLs to identify particular Web pages.A domain name is an identification string that defines a realm of administrative autonomy, authority or control within the Internet. Domain names are formed by the rules and procedures of the Domain Name System (DNS). Any name registered in the DNS is a domain name. Domain names are used in various networking contexts and application-specific naming and addressing purposes. In general, a domain name represents an Internet Protocol (IP) resource, such as a personal computer used to access the Internet, a server computer hosting a web site, or the web site itself or any other service communicated via the Internet.
Every domain name has a suffix that indicates which top level domain (TLD) it belongs to. There are only a limited number of such domains. For example:
gov - Government agencies
edu - Educational institutions
org - Organizations (nonprofit)
mil - Military
com - commercial business
net - Network organizations
 ca - Canada
th – Thailand
pk - Pakistan
Because the Internet is based on IP addresses, not domain names, every Web server requires a Domain Name System (DNS) server to translate domain names into IP addresses.
A domain name can be a maximum of sixty-three characters with one character minimum, and is entered after the protocol in the URL, as you can see in the following example.

What was the first domain?
The first Internet domain name "symbolics.com" was registered by Symbolics, a Massachusetts computer company on March 15, 1985.
By 1992, fewer than 15,000 com domains had been registered.
In the first quarter of 2015, 294 million domain names had been registered.A large fraction of them are in the com TLD, which as of December 21, 2014 had 115.6 million domain names,including 11.9 million online business and e-commerce sites, 4.3 million entertainment sites, 3.1 million finance related sites, and 1.8 million sports sites.As of July 2012 the com TLD had more registrations than all of the ccTLDs combined.
Top-Level Domain Name
The top-level domains (TLDs) such as com, net and org are the highest level of domain names of the Internet which are widely used all around the world. Top-level domains form the DNS root zone of the hierarchical Domain Name System (DNS). Every domain name ends with a top-level domain label.
When the Domain Name System was devised in the 1980s, the domain name space was divided into two main groups of domains.The country code top-level domains (ccTLD) were primarily based on the two-character territory codes of ISO-3166 country abbreviations. In addition, a group of seven generic top-level domains (gTLD) was implemented which represented a set of categories of names and multi-organizations.These were the domains gov, edu, com, mil, org, net, and int.
During the growth of the Internet, it became desirable to create additional generic top-level domains. As of October 2009, 21 generic top-level domains and 250 two-letter country-code top-level domains existed.In addition, the ARPA domain serves technical purposes in the infrastructure of the Domain Name System.
During the 32nd International Public ICANN Meeting in Paris in 2008,ICANN started a new process of TLD naming policy to take a "significant step forward on the introduction of new generic top-level domains." This program envisions the availability of many new or already proposed domains, as well as a new application and implementation process.Observers believed that the new rules could result in hundreds of new top-level domains to be registered.

The Internet Assigned Numbers Authority (IANA) maintains an annotated list of top-level domains in the DNS root zone database.
For special purposes, such as network testing, documentation, and other applications, IANA also reserves a set of special-use domain names.
Second-level and lower level domains
Below the top-level domains in the domain name hierarchy are the second-level domain (SLD) names. These are the names directly to the left of .com, .net, and the other top-level domains. As an example, in the domain example.co.uk, co is the second-level domain.
Next are third-level domains, which are written immediately to the left of a second-level domain. There can be fourth- and fifth-level domains, and so on, with virtually no limitation. An example of an operational domain name with four levels of domain labels is sos.state.oh.us. Each label is separated by a full stop (dot). 'sos' is said to be a sub-domain of 'state.oh.us', and 'state' a sub-domain of 'oh.us', etc.
What is Meant by Sub-Domain?
The Domain Name System (DNS) has a tree structure or hierarchy, with each non-RR (resource record) node on the tree being a domain name. A subdomain is a domain that is part of a larger domain; the only domain that is not also a subdomain is the root domain. For example, west.example.com and east.example.com are subdomains of the example.com domain, which in turn is a subdomain of the com top-level domain (TLD).
It’s easy to create a memorable Web address for unique content areas of your site by using subdomains. A "subdomain" expresses relative dependence, not absolute dependence: for example, techora.net comprises a subdomain of the net domain, and video.techora.net comprises a subdomain of the domain techora.net . In theory this subdivision can go down to 127 levels deep, and each DNS label can contain up to 63 characters, as long as the whole domain name does not exceed a total length of 255 characters. But in practice most domain registries limit at 253 characters.

What is a Name Server?
A name server is a computer hardware or software server that implements a network service for providing responses to queries against a directory service. It translates an often humanly-meaningful, text-based identifier to a system-internal, often numeric identification or addressing component. This service is performed by the server in response to a service protocol request.
An example of a name server is the server component of the Domain Name System (DNS), one of the two principal namespaces of the Internet. The most important function of DNS servers is the translation (resolution) of human-memorable domain names and hostnames into the corresponding numeric Internet Protocol (IP) addresses, the second principal name space of the Internet which is used to identify and locate computer systems and resources on the Internet.

What is DNS (Domain Name Server)?
Domain Name Servers (DNS) are the Internet's equivalent of a phone book. They maintain a directory of domain names and translate them to Internet Protocol (IP) addresses.
The Domain Name System (DNS) is a hierarchical decentralized naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. Most prominently, it translates more readily memorized domain names to the numerical IP addresses needed for the purpose of locating and identifying computer services and devices with the underlying network protocols. By providing a worldwide, distributed directory service, the Domain Name System is an essential and most important component of the better functionality of the Internet.

This is necessary because, although domain names are easy for people to remember, computers or machines, access websites based on IP addresses.

Information from all the domain name servers across the Internet are gathered together and housed at the Central Registry. Host companies and Internet Service Providers interact with the Central Registry on a regular schedule to get updated DNS information.

When you type in a web address, e.g., www.jimsbikes.com, your Internet Service Provider views the DNS associated with the domain name, translates it into a machine friendly IP address (for example 216.168.224.70 is the IP for jimsbikes.com) and directs your own Internet connection to the real and correct website.

After you register a new domain name or when you update the DNS servers on your domain name, it usually takes about 12-36 hours for the domain name servers world-wide to be updated and able to access the information. This 36-hour period is referred to as propagation.
DNS stands for “domain name system” Domain names are the human-readable website addresses we use every day. For example, Google’s domain name is google.com. If you want to visit Google, you just need to enter google.com into your web browser’s address bar.
However, your computer doesn’t understand where “google.com” is. Behind the scenes, the Internet and other networks use numerical IP addresses (“Internet protocol” addresses). Google.com is located at the IP address 173.194.39.78 on the Internet. If you typed this number into your web browser’s address bar, you’d also end up at Google’s website.
We use google.com instead of 173.194.39.78 because addresses like google.com are more meaningful and easier for us to remember. DNS is often explained as being like a phone book – like a phone book, DNS matches human-readable names to numbers that machines can more easily understand.

What is DNS Servers?
Domain name system servers match domain names like google.com to their associated IP addresses — 173.194.39.78 in the case of google.com. When you type google.com into your web browser’s address bar, your computer contacts your current DNS server and asks what IP address is associated with google.com. Your computer then connects to the IP address and displays “google.com” in your web browser – the connection to 173.194.39.78 happens behind the scenes.
The DNS servers you use are likely provided by your Internet service provider (“ISP”). If you’re behind a router, your computer is likely using your router as your DNS server, but the router is likely forwarding requests to your Internet service provider’s DNS servers.

Computers cache DNS responses, so the DNS request doesn’t happen each time you connect to google.com. Once your computer has determined the IP address associated with a domain name, it will remember that for a period of time – this improves connection speed by skipping the DNS request phase. Your computer just needs to connect to Google, not its DNS server and then Google.

Why You Might Want To Use Third-Party DNS Servers?
As we’ve established above, you’re probably using your Internet service provider’s default DNS servers. However, you don’t have to – you can use DNS servers run by a third party instead of your default DNS servers. Two of the most popular third-party DNS servers are OpenDNS and Google Public DNS.
In some cases, these DNS servers may provide you with faster DNS resolves, speeding up your connection the first time you connect to a domain name. However, the actual speed differences you see will vary depending on how far you are from the third-party DNS servers and how fast your ISP’s DNS servers are. If your ISP’s DNS servers are fast and you’re located a long way from OpenDNS or Google DNS’s servers, you may see slower DNS resolves with a third-party DNS server.
OpenDNS also provides optional website filtering. For example, if you enable the filtering, accessing a pornographic website from your network could result in a “Blocked” page appearing instead of the pornographic website. Behind the scenes, OpenDNS has returned the IP address of a website with a “Blocked” messsage instead of the IP address of the pornographic website – this takes advantage of the way DNS works to block websites.

Who Owns the Domain Name?
The Network Information Center (NIC), also known as InterNIC from 1993 until 1998, was the organization primarily responsible for Domain Name System (DNS) domain name allocations and X.500 directory services. From its inception in 1972 until October 1, 1991, it was run by the Stanford Research Institute, now known as SRI International, and led by Jake Feinler. From October 1991 until September 18, 1998, it was run by Network Solutions. Thereafter, the responsibility was assumed by the Internet Corporation for Assigned Names and Numbers (ICANN).
It was accessed through the domain name internic.net, with email, FTP and World Wide Web services run at various times by SRI,Network Solutions, Inc., and AT&T. The InterNIC also coordinated the IP address space, including performing IP address management for North America prior to the formation of ARIN. InterNIC is a registered service mark of the U.S. Department of Commerce. The use of the term is licensed to the Internet Corporation for Assigned Names and Numbers (ICANN).
The Internet Corporation for Assigned Names and Numbers (ICANN) is a nonprofit organization that is responsible for coordinating the maintenance and procedures of several databases related to the namespaces of the Internet - thereby ensuring the network's stable and secure operation. ICANN performs the actual technical maintenance work of the central Internet address pools and DNS Root registries pursuant to the Internet Assigned Numbers Authority (IANA) function contract.
Much of its work has concerned the Internet's global Domain Name System, including policy development for internationalization of the DNS system, introduction of new generic top-level domains (TLDs), and the operation of root name servers. The numbering facilities ICANN manages include the Internet Protocol address spaces for IPv4 and IPv6, and assignment of address blocks to regional Internet registries. ICANN also maintains registries of Internet protocol identifiers.
ICANN's primary principles of operation have been described as helping preserve the operational stability of the Internet; to promote competition; to achieve broad representation of the global Internet community; and to develop policies appropriate to its mission through bottom-up, consensus-based processes.
ICANN was created on September 18, 1998, and incorporated on September 30, 1998 in the state of California. It is headquartered in the Playa Vista neighborhood of the city of Los Angeles.
Which are the best Domain Registration Companies?
A domain name registrar is an organization or commercial entity that manages the reservation of Internet domain names. A domain name registrar must be accredited by ageneric top-level domain (gTLD) registry and/or a country code top-level domain (ccTLD) registry. The management is done in accordance with the guidelines of the designated domain name registries.



There are many popular and the best domain registars are available in the market :
Godaddy
1and1
Network Solutions
NameCheap
Domain.Com