Tài liệu Beginning Microsoft Office Live P2 pptx

If this book makes me rich beyond belief, I may decide to divide my company into eastern

and western divisions, and have a separate web site for each. I can then create subdomains

called east.acxede.net and west.acxede.net and call web servers in those subdomains www.

east.acxede.net and www.west.acxede.net, respectively.

In the United Kingdom, authorities have adopted such a system. The TLD, uk, is divided

into several subdomains. For example, the subdomain for commercial enterprises is co.uk,

and that for educational institutions is ac.uk. If I were to register my domain in the United

Kingdom, I would register it as acxede.co.uk, and my web server would be www.acxede.co.uk.

Translating Domain Names to IP Addresses

While people prefer names to numbers, the reverse is true for computers. People-friendly

names, such as www.acxede.net, which you type into your browser, must be translated into

computer-friendly addresses, such as 216.246.42.123, which web servers understand.

With the help of specialized software called the Domain Name System (DNS), computer

names are automatically translated on the Internet into their IP addresses. Whenever you type

www.acxede.net into your browser, DNS software running on your computer looks up the IP

address of the computer whose name is www.acxede.net and establishes a connection to it

using its IP address.

The DNS software on your computer doesn’t store all possible computer names and their

IP addresses locally. This cross-reference is, in fact, distributed across the Internet. Each

domain has a special server called a domain name server that stores the names of all comput￾ers and their IP addresses in that domain.

Large organizations that maintain their own Internet infrastructure have their own

domain name servers. If you host your domain with a hosting service provider, the HSP will

maintain the domain name server on your behalf.

FAQ

How Does a Web Page Appear in My Browser When I Enter Its Address?

Let’s say you type http://www.acxede.net/default.aspx into your browser. This string is the web

address of the page default.aspx, which resides on a web server named www.acxede.net.

Some people refer to a web address as a URL, which stands for Uniform Resource Locator. No matter

what you call it, it still points to the location of default.aspx on the Web. Your browser splits this string

into three parts: the protocol, the hostname, and the resource name.

The first part, http://, is called the protocol. You can think of a protocol as a method of delivery. Just

as an item you buy online can be shipped to you via United States Postal Service (USPS), FedEx, or some

other shipping method, a file you request from a server on the Internet can be sent to you via one of the

available protocols. The World Wide Web uses the http protocol.

The last part, default.aspx, is called the resource name. It is the name of a resource, such as a web

page, a file, or an image, that resides on the web server.

The part in the middle, www.acxede.com, is the hostname or the name of the web server on which the

resource resides.

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