IP Address and DNS Explained.

Devices in a network are referred to as nodes or hosts.

IP (Internet Protocol) address:-Every electronic device (printers,fax,computer,mobiles,routers,etc.),connected to any particular network has a unique Internet Protocol Address or IP Address.IP addresses are same as the home address or telephone number of any person which is unique.They are the addresses to which the data packets from different servers are send.They are created and managed by the Internet Assigned Numbers Authority(IANA).Anybody can even buy several IP addresses from IANA.
Each IP address is a 32 bit number broken into four (4), eight (8) bit sections(i.e.,it is broken up into four octets). Each section is converted from the binary equivalent to a decimal number. When the IP Address is broken into 4 sections the decimal number ranges from 0 to 255.

Static IP Address :- Static(Permanent) IP Address never changes and is fixed whenever an electronic device connects or disconnects to the Internet.

Dynamic IP Address :- Dynamic IP Address is not static,that is,it changes whenever an electronic device disconnects and connects to the Internet.

STRUCTURE OF AN IP ADDRESS

DNS(Domain Name System/Server) - A service or resource which converts/translates hostnames(domain names,which are easier to remember) into it corresponding IP address.IP address are essential for the communication between devices over the network.IP address is the basis of the whole Internet.When we type www.ipmango.com in the address bar of our browser then the browser contacts the DNS server (mostly provided by our Internet Service Provider) which translates www.ipmango.com into its IP address.Without the IP address of the hostname
(ipmango)the browser will not be able to contact to the host.The DNS server maintains a database of domain names and their corresponding IP address.When it is contacted it searches throughout its database to find the match.If the match is not found it updates its database from some other DNS server on the Internet.The DNS server also has a cache(temporary storage area) for faster access of data as then the server will not have to search through its database.The DNS is quite flexible as multiple IP addresses can be assigned to a single domain which leads
to faster and enhanced surfing.For Example:-google.com has multiple IP addresses which are stored in the DNS server's database and when a browser contacts the DNS server, and a random IP is chosen to contact the hostname(google).To check that which DNS server your computer uses (in windows or linux) just write the command 'nslookup' in command line and hit enter.
NOTE:- DNS lookup translates hostnames into their corresponding IP addresses and Reverse DNS lookup translates IP addresses into their corresponding hostnames.