A Web server is similar to a LAN server except for the fact that it can be accessed over the Internet and it runs specific services related to the Internet. The most common service running on a Web server is Web site hosting service. With Web site hosting service a Web server can host one or many different web sites. Each Web site will have a different IP address. The main function of the Web site hosting service is to support Hypertext Transfer Protocol (HTTP), which serves up Web pages coded with HyperText Markup Language (HTML).
When a Web user desires to access a Web site, they do so by entering, into an application called a Web browser, the IP address of the Web site with the name of the web page they wish to access, or they can enter the domain name of the Web site with the name of the Web page. If they enter the domain name, special servers running Domain Name System (DNS) service will translate the domain name to the IP address.
For example if you enter http://bucarotechelp.com in your Web browser, this sends a request to a DNS server to translate the domain name bucarotechelp.com to its IP address. The current IP address related to bucarotechelp.com is 18.104.22.168. A Web site may change to a different Web site host, and therefore change its IP address, but its domain name will stay the same. The DNS servers on the Internet will simply update their tables to reflect the new IP address.
Note that when you enter a Web site's domain name without identifying a specific page, the Web host service will send the Web site's default Web page (usually named index.html or default.htm).
Most Web servers will also be running File Transfer Protocol (FTP), which allows users to download files and webmasters to maintain their Web site remotely. Most web servers will also be running an email protocol such as Simple Mail Transfer Protocol (SMTP), allowing the server to send and receive mail messages.
There are several different Web server software applications. The most popular Web server software is Apache, which is usually run on the Unix or Linux operating system. A close second popular Web server software is Internet Information Server (IIS) which is usually run on the Microsoft Windows operating system.
Web server software also supports several programming languages. This allows webmasters to develop active websites that may generate Web pages “on the fly”, rather than just serve up static HTML Web pages. The most common programming language used on Apache Web servers is PHP (which originally stood for Personal Home Page. The most common programming language used on IIS is Visual Basic, which is used to create Active Server Pages (ASP).
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