Chapter 11: Network Addressing

Overview

Each computer in a network must have its own unique address so that other network members can find it to exchange data. Thus, a network is something akin to a telephone system. To call someone, you have to dial that person's number, not his or her name .

When you are requesting a Web page from a server, you need to know the page's IP address. Once you know the address and send your request to the server, you have to supply it with your own IP address so that the server knows where to return the requested page. Here, an analogy with the regular mail can be observed . If you want to receive an answer to your letter, you have to put your return address on the envelope.

At the dawn of the Internet, the number of computers in it was not that large, and the simplest and most logical method of implementing addressing was selected: using numbers . Still, 20 numerical addresses is about the limit an average human can remember, so for the convenience of humans , hosts are given names that can be easily remembered , for example, www.webpage.com .

These two addressing systems are incompatible, and something had to be done about this. This was solved by creating a centralized database of numerical IP addresses and their corresponding symbolic host names. This allows users to enter a symbolic address into a program, which then looks up the corresponding numerical IP address in the centralized database and uses this address to connect to the necessary computer.

This made the situation with remembering addresses much easier for people. Now to visit a site, for example, of the Microsoft Corporation, you have to know not its exact numerical IP address but just an easy-to-remember domain name: www.microsoft.com .



Hacker Linux Uncovered
Hacker Linux Uncovered
ISBN: 1931769508
EAN: 2147483647
Year: 2004
Pages: 141

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