Human minds are not configured to memorize strings of numbers separated by dots. But computers are. They talk to each other using these numbers. These are their names by which they identify and communicate with each other.
# What’s an IP Address
These machine names or numbers, which are known as IP addresses, are made up of four octets, whose value ranges from 0 to 255. Each IP address is unique, and can be the name of only one computer.
To get a better understanding, you can compare IP addresses to door numbers. When you search for a term on Google, your computer sends your query to this IP address, because this is the computer where the Google website lives. The same happens in the case of Yahoo.
The IP addresses may be permanent or temporary, but each one is unique. You can imagine the confusion if this was not so. The Internet would be like a country without addresses, where you had to be extremely lucky to reach a destination of your choice.
# Who allots IP addresses
The authority that ensures that every computer has only one name when it connects to the Internet is the Internet Assigned Numbers Authority, popularly known as IANA. It has built a hierarchical system to ensure that there is no overlapping or duplication of numbers, and that there is a record of each IP address being used on the net.
IANA has also set up regional bodies to look after different continents. Thus, for India the IANA body that allots IP addresses is Asia Pacific Network Information Centre. It is through this organisation that Internet Service Providers in India like BSNL, Airtel or Reliance obtain the IP addresses that they then allot to their Indian customers.
The IP addresses can be temporary or permanent, according to usage. For instance, a broadband user is allotted a permanent IP address. This IP address then becomes the identity of this user’s computer. The other computers know the destination where information is to be sent.
For instance, when this user based in Delhi types Google.com in the search bar, his computer first locates the machine name of Google.com. It then sends a message to the computer where Google resides saying his boss wants to visit Google. This message may be routed through hundreds of computers before it reaches Google but Google knows where the message has come from. It responds by sending a message back to the IP address of the computer. The connection is made, and communication begins.
But not everyone in India is lucky to have a broadband connection. There are lakhs of Indians who use a dial up connection to access the net. In these cases, the service providers, like BSNL, provide temporary or floating IP addresses to the user.
Thus, the computer of a Chennai resident, who has a dial up account with BSNL, will be allotted a temporary IP address by BSNL the moment he logs onto the net. This gives the user’s machine an identity to talk to other machines on the net, and to fetch requests made by the user. This identity lapses the moment the user logs out. The floating IPs enable ISPs to serve a large number of users as against the fixed IPs whose usage is restricted.
So, next time you log on to the net, try and identify the machine name of your host.