The domain name system (DNS) is the way that internet domain names are
located and translated into internet protocol (IP) addresses. The domain name
system maps the name people use to locate a website to the IP address that a
computer uses to locate a website.
It is the system used to translate
alphanumeric domain names into Internet protocol numbers. It simply converts
the names typed in the web browser address bar into IP addresses. The DNS is a
distributed database arranged hierarchically; its purpose is to provide a layer
of abstraction between internet services and the numeric address(IP address)
used to uniquely identify any given machine on the Internet.
WORKING:
The DNS makes it possible to assign domain names in a meaningful way to
internet resources as well as to users, regardless of the entity's location.
Coordinates across the internet are
maintained using a complex authoritative root system known as Toplevel
Domain(TLD) as well as DNS and other smaller name servers responsible for
hosting individual domain information.
DNS includes three types of
top-level domains: generic(gTLD), Country code(ccTLD), Sponsored(sTLD). gTLD's
include domains that could be obtained by anyone(.com, .info, .net, .org).
Since 2014 many other gTLD's have been added like .pub, .ngo, .sucks. sTLDs are
limited to a specific group. For example, .aero.
The DNS spreads
the responsibility for each domain by mapping the domain names and assigning them to IP
addresses, and vice-versa. This is accomplished through authoritative name
servers which have been designated for each domain. Each authoritative name
server is responsible for its own particular domain, but it has the authority
to assign a new authoritative name server to any of its sub-domains. The DNS can store many types of information, even the mail server lists for specific domains. The DNS is a core element that ensures However, the DNS does
not include security extensions, which were instead developed as DNSSEC.
TOP-LEVEL DOMAIN:
It is the last part of the name. eg: .com, .org, .net etc....It usually
classified into two,
·
Generic top-level domains(gTLDs)
·
Country code
top-level domains(ccTLDs)
The entity responsible
for the administration of these TLDs in the 'root' of the DNS is the Internet
Assigned numbers Authority(IANA) that is currently operated by the Internet
Corporation for Assigned names and numbers(ICANN).
SECOND-LEVEL DOMAIN:
The next part of the domain name to
the left of the TLD is the "Second Level Domain". These are the
domains that you are typically able to register with a registrar.
Eg., xtension.in
The next part of the domain name to
the left(www...) would be called "Third-level Domain", and so on.
gTLD:
gTLDs are the TLDs that do not field to any specific country and are
"generic" in terms of being able to be used by anyone on the internet
anywhere in the world. The "original" TLDs such as .com, .org are all
classified as "generic TLDs". There were a couple of rounds of "expansion"
of the gTLDs that brought the total to 22gTLDs before the "new
gTLD" expansion is currently underway.
ccTLD:
ccTLDs are two-letter TLDs that are assigned to countries based on the ISOC
3166 list of country codes. Some countries have chosen to operate their ccTLD
exclusively for domains with their country or geographic territory.
Eg., .uk, .co.uk, .org.uk.
new gTLD:
It uses almost any text string(and in multiple character sets).
IDN(International Domain Name):
The Original TLDs were all in the ASCII character set, but over time, IDN
was created. It uses other character sets such as Cyrillic, Arabic, Chinese,
Korean etc. The IDN for a country code TLD appeared in 2010 and the new gTLDs
contain many IDNs.
This is a reference Blog