What is a domain name? What website name? What is a URL?

What is a domain name?

 In reality, there are too many domain names to use, but do you understand the detailed meaning of domain names? Do you know what the domain name is? Below, Xiaobian will take you through the meaning of the domain name.

Domain name, I believe that everyone is not default, and has been used countless times! such as:

Google.com, baidu.com, 163.com, etc.

At this time, you may have to wonder why Xiaobian did not add www in front.

Because under normal circumstances, should not be www.baidu.com and the like?

Here, Xiaobian can tell you clearly, plus www, it is no longer a domain name!

Let us analyze the following paragraph:

Http://mail.163.com/index.html

1) http://: This is the protocol, which is the HTTP hypertext transfer protocol, which is the protocol for web pages to be transmitted over the Internet.

2) mail: This is the server name, which represents a mailbox server, so it is mail.

3) 163.com: This is a domain name, a unique name used to locate a website.

4) mail.163.com: This is the name of the website, consisting of the server name + domain name.

5) /: This is the root directory, that is, the server is found by the website name, and then the root directory of the web page is stored on the server.

6:) index.html: This is the default page in the root directory (of course, the default page of 163 is not this I don't know, but most of the default pages are index.html)

7) http://mail.163.com/index.html: This is called URL, Uniform Resource Locator, global address, used to locate resources on the Internet.

Maybe at this time, you still don't understand, what is the difference between this domain name and the website name?

OK, Xiaobian to tell you!

For example, you bought a university whose name is myname.com.

Then, you want to establish a language department, so the liberal arts building was established, called yuwen.myname.com

Then, you want to build a math department, OK, shuxue.myname.com is established.

Like 163, his domain name is 163.com, he wants to build a www server, so he has www.163.com.

He wants to play the mailbox server again, so mail.163.com also has it.

In this way, do you understand?

Well, just mentioned:

Http://mail.163.com/index.html

Among them, index.html is the default web page.

However, when we enter the URL, we usually enter it directly.

Mail.163.com or www.baidu.com, why is this?

Then look down.

Be aware that we can not only access files, but also access directories.

such as:

Http://www.163.com/

This means accessing the current root directory /.

If you don't know what the root directory is, please check Baidu. I won't go into it here.

At this point, the web server will check if it has this directory, OK, definitely. So, will the server return the entire directory to you? No!

The server will look for the default web page in its own directory, usually index.html, of course, you can modify it by configuring the web page. Xiaobian built Apache under LINUX, there are configuration files specifically modified, you can also try.

After that, the server finds the index.html in the directory and returns it to the web browser.

Therefore, when we visit www.baidu.com, the browser will automatically add http:// to us and become http://www.baidu.com.

And Baidu's server, after receiving the request, will automatically add /, become:

Http://www.baidu.com/.

Then, Baidu server will look for index.html or other default webpages in this directory, which is Baidu's homepage. After it is found, it will be returned to you through the http protocol. That is the Baidu homepage you saw.