Translations by Heikki Mäntysaari

Apache Modules

For example, when a user requests the page http://www.example.com/this_directory/, he or she will get either the DirectoryIndex page if it exists, a server-generated directory list if it does not and the Indexes option is specified, or a Permission Denied page if neither is true. The server will try to find one of the files listed in the DirectoryIndex directive and will return the first one it finds. If it does not find any of these files and if Options Indexes is set for that directory, the server will generate and return a list, in HTML format, of the subdirectories and files in the directory. The default value, found in <filename>/etc/apache2/apache2.conf</filename> is " index.html index.cgi index.pl index.php index.xhtml". Thus, if Apache2 finds a file in a requested directory matching any of these names, the first will be displayed.

The Apache2 web server is available in Ubuntu Linux. To install Apache2:

File Permissions

HTTPD - Apache2 Web Server

Apache is the most commonly used Web Server on Linux systems. Web Servers are used to serve Web Pages requested by client computers. Clients typically request and view Web Pages using Web Browser applications such as <application>Firefox</application>, <application>Opera</application>, or <application>Mozilla</application>.

Users enter a Uniform Resource Locator (URL) to point to a Web server by means of its Fully Qualified Domain Name (FQDN) and a path to the required resource. For example, to view the home page of the <ulink url="http://www.ubuntu.com">Ubuntu Web site</ulink> a user will enter only the FQDN. To request specific information about <ulink url="http://www.ubuntu.com/support/paid">paid support</ulink>, a user will enter the FQDN followed by a path.

The most common protocol used to transfer Web pages is the Hyper Text Transfer Protocol (HTTP). Protocols such as Hyper Text Transfer Protocol over Secure Sockets Layer (HTTPS), and File Transfer Protocol (FTP), a protocol for uploading and downloading files, are also supported.

Apache Web Servers are often used in combination with the <application>MySQL</application> database engine, the HyperText Preprocessor (<application>PHP</application>) scripting language, and other popular scripting languages such as <application>Python</application> and <application>Perl</application>. This configuration is termed LAMP (Linux, Apache, MySQL and Perl/Python/PHP) and forms a powerful and robust platform for the development and deployment of Web-based applications.

Basic Settings

The <emphasis>ServerAdmin</emphasis> directive specifies the email address to be advertised for the server's administrator. The default value is webmaster@localhost. This should be changed to an email address that is delivered to you (if you are the server's administrator). If your website has a problem, Apache2 will display an error message containing this email address to report the problem to. Find this directive in your site's configuration file in /etc/apache2/sites-available.

The <emphasis>Listen</emphasis> directive specifies the port, and optionally the IP address, Apache2 should listen on. If the IP address is not specified, Apache2 will listen on all IP addresses assigned to the machine it runs on. The default value for the Listen directive is 80. Change this to 127.0.0.1:80 to cause Apache2 to listen only on your loopback interface so that it will not be available to the Internet, to (for example) 81 to change the port that it listens on, or leave it as is for normal operation. This directive can be found and changed in its own file, <filename>/etc/apache2/ports.conf</filename>

Default Settings

This section explains configuration of the Apache2 server default settings. For example, if you add a virtual host, the settings you configure for the virtual host take precedence for that virtual host. For a directive not defined within the virtual host settings, the default value is used.

The <emphasis>DirectoryIndex</emphasis> is the default page served by the server when a user requests an index of a directory by specifying a forward slash (/) at the end of the directory name.

<emphasis role="bold">ExecCGI</emphasis> - Allow execution of CGI scripts. CGI scripts are not executed if this option is not chosen. <placeholder-1/>

For security reasons, this should usually not be set, and certainly should not be set on your DocumentRoot directory. Enable this option carefully on a per-directory basis only if you are certain you want users to see the entire contents of the directory.

<emphasis role="bold">SymLinksIfOwnerMatch</emphasis> - Only follow symbolic links if the target file or directory has the same owner as the link.

<emphasis role="bold">LockFile</emphasis> - The LockFile directive sets the path to the lockfile used when the server is compiled with either USE_FCNTL_SERIALIZED_ACCEPT or USE_FLOCK_SERIALIZED_ACCEPT. It must be stored on the local disk. It should be left to the default value unless the logs directory is located on an NFS share. If this is the case, the default value should be changed to a location on the local disk and to a directory that is readable only by root.

<emphasis role="bold">PidFile</emphasis> - The PidFile directive sets the file in which the server records its process ID (pid). This file should only be readable by root. In most cases, it should be left to the default value.

<emphasis role="bold">User</emphasis> - The User directive sets the userid used by the server to answer requests. This setting determines the server's access. Any files inaccessible to this user will also be inaccessible to your website's visitors. The default value for User is www-data.

Unless you know exactly what you are doing, do not set the User directive to root. Using root as the User will create large security holes for your Web server.

The Group directive is similar to the User directive. Group sets the group under which the server will answer requests. The default group is also www-data.

sudo apt-get install libapache2-mod-auth-mysql

HTTPS Configuration

sudo a2enmod ssl

Types of Certificates