DOMAIN NAME
1. Internet domain names are easier to remember than IP addresses.
2. An important purpose of domain names is to provide easily recognizable and
memorial names to numerically addressed Internet resources. This
abstraction allows any resource (e.g., website) to be moved to a different
physical location in the address topology of the network, globally or locally
in an intranet. Such a move usually requires changing the IP address of a
resource and the corresponding translation of this IP address to and from its
domain name.
A domain name is an identification label to define realms of administrative
autonomy, authority, or control in the Internet, based on the Domain Name
System (DNS).
Domain names are also used as simple identification labels to indicate
ownership or control of a resource
Domain name appear as a component in Uniform Resource Locators (URLs)
for Internet resources such as web sites.
For Example:
URL: http://www.example.net/index.html
Domain name: www.example.net
Registered domain name: example.net
HIERARCHY OF DOMAIN NAME:
There is no limitation of sub-domain level or domain hierarchy.
Top-level domains
Every domain name ends in a top-level domain (TLD) or first-level domain
name, which is always either one of a small list of generic names (three or
more characters), or a two-character territory code.
Prominent examples are the top-level Internet domains .com, .net and .org.
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.
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.
Second-level (or lower-level) domain names are often created based on
the name of a company, product or service.
DOMAIN NAME SYSTEM
Domain Name System (DNS) is a hierarchical naming system for
computers, services, or any resource participating in the Internet.
It translates domain names meaningful to humans into the numerical (binary)
identifiers associated with networking equipment for the purpose of locating
and addressing these devices world-wide.
The Domain Name System makes it possible to assign domain names to
groups of Internet users in a meaningful way, independent of each user's
physical location. Because of this, World Wide Web (WWW) hyperlinks and

Internet contact information can remain consistent and constant even if the
current Internet routing arrangements.
The Domain Name System distributes the responsibility of assigning domain
names and mapping those names to IP addresses by designating authoritative
name servers for each domain.
WEB SERVER
1. A computer program that is responsible for accepting HTTP requests from
clients, and serving them HTTP responses along with optional data contents,
which usually are web pages such as HTML documents and linked objects
(images, etc.).
Vendor Product Web Sites Hosted Percent
Apache Apache 96,531,033 52.05%
Microsoft IIS 61,023,474 32.90%
Google GWS 9,864,303 5.32%
nginx nginx 3,462,551 1.87%
lighttpd lighttpd 2,989,416 1.61%
Oversee Oversee 1,847,039 1.00%
Others - 9,756,650 5.26%
Total - 185,474,466 100.00%
ISSUES OF DOMAIN NAME REGISTRATION
 Check the domain name first, whether domain name is valid or not.
 Domain name cannot register if it was already reserved.
 The availability of the domain name can be checked in whois.com,
whois.net, etc. if domain name is not reserved or available then we go for
registration.
 An end-user cannot directly register and manage their domain name
information with ICANN. A designated registrar must be chosen.
 When a registrar registers a .com domain name for the end-user, it must
pay a maximum annual fee of US$6.86 to VeriSign and a US$0.20
administration fee to ICANN. VeriSign is the registry manager for .com
gTLD.
 Most domain registrars price their services and products to address both the
annual fees and the administration fees that must be paid to ICANN.
 The maximum period of registration of a domain name is generally 10
years.