当我们使用我们最喜欢的浏览器访问一个网站时，我们通常只需输入URL的基本部分，就可以毫无问题地“到达”所需的位置。但是，我们现在是否已经到了可以开始从所有网站的URL中省略“www”的地步，或者仍然有必要添加它？

今天的问答环节是由SuperUser提供的，SuperUser是Stack Exchange的一个分支，是一个由社区驱动的问答网站分组。

问题

超级用户读者Celeritas想知道在网站URL中添加“www”是否有区别：

In modern web browsers, is there any point in putting ‘www’ in front of a website URL that uses it? When going to ‘www.facebook.com’ or ‘www.cbc.ca’, is there any benefit or difference made by omitting the ‘www’?

现在是否真的有必要将“www”添加到网站url中，或者您可以在浏览互联网时忽略它而不遇到任何问题？

答案

超级用户贡献者Synetech为我们提供了答案：

It usually doesn’t, but it could.

This has nothing to do with the browser; it has to do with the web-server. The web-server is a computer (or even multiple computers) which receive queries for web-pages and send the appropriate data. A URL includes several parts, one of which is the name or address of the web-server.

Many companies host more than just a web-server, they may also run an FTP-server, a database-server, a mail-server, and so on. These could be hosted from the same machine as the web-server or on different machines.

In the past, it was common to specify the difference via a prefix for c***istency. So for example, Acme Industries might buy the domain-name ‘acme.org’, then set up one or more computers to host the different services they have. When you want to use one of the services, you enter the appropriate host name:

So why does it still work without ‘www’? Because most web-servers allow you to accept different URLs and redirect them as necessary. For the convenience of users, most companies and organizati*** set up a rule to have the web-server handle connecti*** to the hostname on port 80 (the “web port”), or redirect it to another system if the web-server is a different machine.

Differentiating the service or machine being accessed can also be done through the port, but it requires specifically including it in the name, so it’s not really any better than using prefixes:

Sometimes the scheme can perform this function:

Using schemes works as well and can be done automatically using the appropriate software (e.g., a browser would add ‘http://’, an email client would add ‘pop://’, etc.). But there are not official schemes for every type of server that can exist, and inventing one is not ideal because it would require software to support it.

It’s becoming less and less necessary to include ‘www’, but it is not universal, and some sites still require it because it helps keep things organized.

大多数情况下，我们可以愉快地（很容易地）省去在我们最喜欢的网站的网址的“www”部分键入，但总有一种可能性，你可能会遇到“罕见”的网站，仍然需要它。

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