Describe the functions of DNS Server?

DNS is the service used to convert human readable names of hosts/domains to IP addresses.

Domain Naming Service - For resolving the domain name to IP address

DNS function is primarily a name resolver and maintain multiple records:

1) A Record (IPv4) and AAAA (IPv6)  = Domain Name to IP Address Mapping

2) PTR/Reverse Record = IP Address to Name Mapping

3) MX Record = Required to configured for Email Servers hosted in the domain

Furthermore there are two types of DNS Servers:

1) Authoritative: Authorized DNS Server for Zone file of Specific Domain

2) Recursive: Non-Authoritative DNS, acts as the relay between client and authoritative DNS Server. Forward Queries and Maintain local cache for frequent records to improve performance.

A DNS server resolves a hostname to an IP Address

DNS   Server is a system to for naming computers and network services in a  TCP ip network or domain.

DNS  server resolve address to IP and then its Reverse look up zone resolve it ip to address.

Easier & every one can remember 

to make it as simple as possible

it has only a list of 2 things

Domain name:                                                      ip address:

google.com                                                         94.128.0.163

hotmail.com                                                        65.55.77.28

.......

and so on

they made it just to make things simple for peoples, as its hard to memorize numbers such as:65.55.77.28

its much easier to memorize domain names such as:

hotmail.com

as simple as that

ill add more details about DNS but thats for security subject

DNS servers must have the best security ever!...

Why?

because if someone hacked a dns server and changed the server ip of google.com for example to his servers ip which contains malicious of any kind like virus or trojan, imagine how many users/computers will be infected as the most visited website is google.com

thats why they secure the DNS very tightly and uses high reliable servers such as Unix/Linux

regards

Domain Name System (DNS) is a solution to map human readable names to corresponding IP Addresses (IPv4 or IPv6) and vice versa, in big networks. Domain Name System (DNS) was originally developed for name resolution in the early days of the Internet.

Resloving Host Namea to IP address and IP address to Host Names.

It resolves query from a workstation and checks the stored name of requested IP or Hostname against its database.