All about IP addresses

I feel that the first and foremost thing to learn hacking is to know about IP address. So i am starting my hacking related posts with IP address.
In this post i have written all the basic concepts of IP addresses.
My next post will be on hacking IP address of a remote computer.
So before that lets have a glance at the basics of IP..


What is an IP address?
If a post man wants to deliver a letter to you, first he needs to know the address of your home. In the same way Computers on the Internet need to find one another in order to communicate. Each computer therefore has a unique identifying number known as an IP address.
Simply.. Every system connected to internet must have a unique address. This address is called IP address.
Every URL (say, “www.google.com”) has its own numbered Internet Protocol or IP address.
An IP address looks something like this:74.125.19.147
An IP address is a series of numbers that tells us where a particular device is on the Internet network.


Public IP address
A public IP address is assigned to every computer that connects to the Internet where each IP is unique. Hence there cannot exist two computers with the same public IP address all over the Internet. This addressing scheme makes it possible for the computers to “find each other” online and exchange information. User has no control over the IP address (public) that is assigned to the computer. The public IP address is assigned to the computer by the Internet Service Provider as soon as the computer is connected to the Internet gateway.

Public IP addresses can be divided into two types.

They are STATIC and DYNAMIC..

what is static IP?

A static IP address does not change and is used primarily for hosting webpages or services on the Internet. 

Disadvantages of static configuration

This requires manual configuration of each and every computer.

Every time care must be taken that no two systems should have same IP.

This manual configuration has many problems when number of systems increase.

Dynamic IP

On the other hand a dynamic public IP address is chosen from a pool of available addresses and changes each time one connects to the Internet. Most Internet users will only have a dynamic IP assigned to their computer which goes off when the computer is disconnected from the Internet. Thus when it is re-connected it gets a new IP.

To do this Dynamic Host Configuration Protocol (DHCP) was developed.

A DHCP server is a software program that assigns IP addresses to computer dynamically.

Advantages

Administrators of large networks save hundreds of hours per year over manual configuration of computers.

No IP address conflict.

Users need not know about manual configuration.

Private IP address

An IP address is considered private if the IP number falls within one of the IP address ranges reserved for private networks such as a Local Area Network (LAN). The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private networks (local networks):

10.0.0.0 – 10.255.255.255 (Total Addresses: 16,777,216)

172.16.0.0 – 172.31.255.255 (Total Addresses: 1,048,576)

192.168.0.0 – 192.168.255.255 (Total Addresses: 65,536)

How to find your Private IP?

go to start->open RUN->type cmd. Then command prompt will be opened->type the command "ipconfig" without brackets. 

The number that you see against “IPV4 Address:” is your private IP.

How to find your public IP?

You can check your public IP address by visiting www.whatismyip.com