Web 101

Domain Name

An alias for the actual address of your web.

Essential Need - A Registrant e.g. to check if the name you want for your site is available, to register the name (typical prices range from $15.00 to $35.00 for one year) and to set up your Web Host's Name Server information ... e.g. BestHost.NS1 and BestHost.NS2 .

Background - Several 'lookup' steps are required for a visitor to find your site - luckily, a whole bunch of browser and computer software does all the hard work:

First of all, a potential visitor to your site will start by typing your domain name in the browser and hitting [enter] or clicking on [go]. The browser program prepares a little message which is sent from the visitor's computer to his or her Internet Service Provider (ISP). This request to visit YOURSITE.COM involves sending the domain name in a little packet of information, which also includes the unique identity of the visitors own computer by the way, via a router (or a series of routers) to your Domain Name Registrant's Domain Name Server - an on-line electronic directory. There it looks up your domain name and finds which web host should be contacted. In fact it finds the I.P. address of your web host's 'Name Server'. The electronic 'message' requesting data from your site then wings its way to the appropriate server.

The second step that takes place at your Web Host's Name Server may also be somewhat complex. Your Domain Name is looked up again, and its 'current' address is obtained. This specific address is a unique 32 bit digital address known as an IP (for Internet Protocol) Address - but your files may reside anywhere within one or several fairly complex directory trees. Your site may in fact be distributed between several different servers! The message (or packet) is now directed to yet another 'Router' which belongs to the Web Hosting Service and this one manages the actual routing of the request message.

This third step results in the surfer's message being handled by 'your' Server and the data from or copy of your main web page (often called Home Page) begins to be sent back to the originator by a similar method, in most cases requiring many 'hits' to transfer all the data and graphics. Yes, this is a simplification - you may be surprised to learn that its not unusual for 15 to 20 machines dotted all over the planet to be involved in transmitting these messages (or 'packets') back and forth.

If a user knows the actual IP Address of the website, she may actually enter that value in the browser and gain access to your site, however if the IP Address changes, contact will be lost! So ... in order for the Web's 200 Million to be able to visit your site on a daily basis, you have to 'register' your Domain Name and provide the Web Host's Name Server identification to the registry service also. By now you'll have realised the common suffixes .NS1 and .NS2 stand for 'Name Server 1 & 2'.

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Domain Name Registrant

A company that has a license to issue unique domain names and maintain domain name servers.

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Domain Name Server

A specialized computer (or many computers) mapping the plain text domain name to the I.P. Address of the name servers at your favourite website hosting company - see Host.

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Host

The company that owns / leases / manages the computer(s) that store your web site pages and other files. They must have very high bandwidth connections to the net otherwise your site will not load quickly to users browsers.

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HTML

Stands for Hyper Text Mark-Up Language. You are reading an HTML page at this moment.

If you look at the source of this page ( in I.E. click [view][source] ) you will see browser instructions enclosed in "<" and ">" symbols - called "tags" that define features such as bold or italic and underline .

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IP Address

Essential Need - You will see this frequently. IP means 'Internet Protocol' and if you are 'on-line' you have an 'IP Address'. Each Internet Service Provider (ISP) is allocated a range of IP addresses ... depending on your connection e.g. Dial-Up or ADSL or Cable, and your provider, you will have a 'Static' or 'Dynamic' IP Address. At home I am lucky enough to have a 'Static' address which means it stays the same no matter what - most people have a 'dynamic' address, which means that every time they log on they will be allocated a new IP address from the list of addresses belonging to the particular ISP.

Background - An IP Address is written in the form xxx.xxx.xxx.xxx where each xxx can be any decimal value between 001 and 255. These decimal numbers represent the range of an 'eight bit' binary number ... there are 'four' numbers, so the whole address is a '32 bit' address:

decimal\binary	b7	b6	b5	b4	b3	b2	b1	b0	hex
000	0	0	0	0	0	0	0	0	00
001	0	0	0	0	0	0	0	1	01
002	0	0	0	0	0	0	1	0	02
003	0	0	0	0	0	0	1	1	03
004	0	0	0	0	0	1	0	0	04
005	0	0	0	0	0	1	0	1	05
006	0	0	0	0	0	1	1	0	06
007	0	0	0	0	0	1	1	1	07
008	0	0	0	0	1	0	0	0	08
009	0	0	0	0	1	0	0	1	09
010	0	0	0	0	1	0	1	0	0A
011	0	0	0	0	1	0	1	1	0B
012	0	0	0	0	1	1	0	0	0C
013	0	0	0	0	1	1	0	1	0D
014	0	0	0	0	1	1	1	0	0E
015	0	0	0	0	1	1	1	1	0F
016	0	0	0	1	0	0	0	0	10
\|
099	0	1	1	0	0	0	1	1	63
100	0	1	1	0	0	1	0	0	64
101	0	1	1	0	0	1	0	1	65
\|
255	1	1	1	1	1	1	1	1	FF
value for a '1' ~	128	64	32	16	8	4	2	1

ISP

These initials stand for "Internet Service Provider" - which can be your telephone company, your cable company or any of several hundred companies, some of which use satellites and the telephone.

MODEM

A device which allows your computer to connect to the telephone line. In the home, an 'external modem' is often provided for cable or DSL connections, while a regular 'phone connection is usually made with an 'internal modem'.

ROUTER

A specialized computer which is designed to connect multiple computers to a network and handle communications back and forth. Many homes now have small routers ~ particularly if they have ADSL or DSL connections.

SERVER

Almost any computer can be a 'server' these days - Windows 2000 professional includes software to allow server software to be run for example, and Microsoft also provides PWS (Personal Web Server) software for Win 98.

Typically, a set of web pages - a website - is hosted on a Server ... and the computers on a network that can connect to the server are known as Clients.