Internet..which simply means network of interconnected devices.
Most people think that Internet is kind of a hub, but its not. Internet is more complex to understand than to use it.
So internet is not actually a hub, there is not a single server which can serve whole internet. Internet is more of a one to many relation thingy… Server serves to more than one client at a time, but connection between individual client and server is peer to peer. So actually the flow of site request goes as – Client–>DNS (Domain Name Server)–> Server–> Back to client.
When you write site address(URL) in browser, what happens is your browser sends a request to DNS to get the IP address of server, DNS then resolves IP and sends IP to browser which then establishes TCP connection with server . Then on receiving request of client, server sends its data back to client. This is it, sounds simple process but a lot more happens under the hood.
Also, www(World Wide Web) which one writes in browser is actually a information space where media, documents are identified by URL(Uniform Resource Locator). www was first created at CERN, Geneva, Switzerland. It was first used to transfer data between two computers.
DNS (Domain Name Server) – DNS is actually kind of a mediator between client and server. Thing is, Server is hosted on an IP address but remembering IP address is quite difficult so what DNS does is, it links domain name(site name) with its IP address. So when you type domain name in browser it sends to DNS and then DNS resolves IP and provides that IP to browser. There are many free public DNS available like Google Public DNS (IPv4 – 126.96.36.199), OpenDNS (IPv4 – 188.8.131.52), etc.
IP (Internet Protocol) Address – IP address is a numerical label assigned to each device which is connected to a network and uses internet protocol to communicate with network. There are two IP versions :
- IPv4 (Internet Protocol version 4) : IPv4 address are 32bit long, thus total number of unique possible addresses are 2^32. Its in format of eg: 123.456.789.123. There are 4 octets, each octet is of 8 bit thus total summing up to 32 bits. IPv4 has many protocols which serves unique purposes, eg: TCP, UDP, etc.
- IPv6 (Internet Protocol version 6) : IPv6 is most recent version of Internet Protocol, it uses 128bit address, thus allowing 2^128 possible unique addresses. IPv6 is better in many ways then IPv4, including but not limited to Security, Payload size, Address space, etc.