Web servers are the backbone of the Internet, they are hosting all pages, including search engines and serve as the basis for all types of web application, including webmail. In the future, this trend will be accentuated with dynamic web pages and web applications increasingly replacing desktop applications.

According to Netcraft, a little over 50% of the world's web servers run Apache(http://news.netcraft.com/archives/web_server_survey.html), most of them on Linux. The actual percentage is actually slightly higher because a large number of administrators configure their servers to disseminate false information on the web server used, not to provide any information that could facilitate attacks. These servers unidentified appear in the research as "other".

In the early days of the Internet, were used only static HTML pages and CGI scripts. Apache itself continues to support only these basic features, but it can be extended through modules, going to support PHP scripts, access MySQL databases, among many other features. Where is requested a page in PHP or another language, comes into the appropriate module, which makes the necessary processing and returns to the Apache html page that appears. Into action, then the content managers and forums, which combine the features of PHP with a database such as MySQL, accessed through it. The combination of all this form the solution that is popularly called "LAMP" (Linux + Apache + MySQL + PHP).

Apache and MySQL, with PHP support may also be installed on Windows (forming the "WAMP"), a popular solution for Microsoft that administrators do not feel comfortable using IIS.

Besides being one of the oldest web servers and one of the safest, Apache has several modules that add support for more exotic features. Most of the current page uses a PHP structure, often with a MySQL database or PostgreSQL. There are even very tos systems ready, such as phpBB (forum) and WordPress (Content Management), which can be installed without much difficulty after the web server is already running. Other rec bears are popular encryption SSL pages necessary to create secure pages (used in stores, for example) systems and reporting access, such as Webalizer.

In addition to the web server itself, you almost always will also need to configure a DNSserver, which accounts for the domain of your site or company. Learn how to configure DNS correctly is important, otherwise you may have trouble sending e-mails (the lack of reverse DNS), or even have more serious problems with the registration of the domain.

The Apache to host multiple sites on the same server feature called virtual hosts. Only the most accessed sites are able to saturate the resources of a dedicated server configuration Okay, so I host multiple sites on the same server is a way to save resources and labor.

When hosting multiple sites, we now have two new problems: we need to offer some form of access to files, so that those responsible can update your pages without changing files from neighbors, and we need a quota system so that each one has its share just disk space.

We then created multiple logins to access and configure an FTP server, so that everyone has access to their own files, but without changing the others. Although widely used, the FTP is insecure. He is actually a file server for general use, that is not limited to use in conjunction with a web server. It is very common to use an FTP server to make files available for public download, for example.

Completing the team, we have a quota, which allows you to limit the disk space used by each User, ensure the equitable sharing of available resources. In reaching its limit, the User receives a message "disk full" even though there are still several GB free hard disk's server.