The Red Hat httpd.conf File


The Red Hat httpd.conf File

This section highlights some of the important features of the Red Hat httpd.conf file, which is based on the httpd.conf file distributed by Apache. This heavily commented file is broken into the following parts (as is this section):

  1. Global Environment: Controls the overall functioning of the Apache server.

  2. Main Server Configuration: Configures the default server (as opposed to virtual hosts) and provides default configuration information for virtual hosts.

  3. Virtual Hosts: Configures virtual hosts. For more information refer to "" on page .

Section 1: Global Environment

ServerTokens

The ServerTokens directive (page ) is set to OS, which causes Apache, when queried, to return the name of the operating system and the complete version number of Apache: 

ServerTokens OS

ServerRoot

The ServerRoot directive (page ) is set to /etc/httpd, which is the pathname that Apache prepends to relative pathnames in httpd.conf: 

ServerRoot "/etc/httpd"

<IfModule>

Multiprocessing modules (MPMs) allow you to change the way Apache works by changing the modules it uses. The <IfModule> containers (page ) allow you to use the same httpd.conf file with different modules: The directives in an <IfModule> container are executed only if the specified module is loaded.

The section of httpd.conf that starts with the comment 

## Server-Pool Size Regulation (MPM specific)

holds two <IfModule> containers (page ) that configure Apache, depending on which module, prefork or worker, is loaded. Red Hat ships Apache with the prefork module loaded; this section does not discuss the <IfModule> container for the worker module. (See the comments in the /etc/sysconfig/httpd file if you want to load the worker module.)

The prefork <IfModule> container, shown below, holds directives that control the functioning of Apache when it starts and as it runs: 

<IfModule prefork.c>
StartServers       8
MinSpareServers    5
MaxSpareServers   20
ServerLimit      256
MaxClients       256
MaxRequestsPerChild  4000
</IfModule>

Listen

FEDORA The Listen directive (page ) does not specify an IP address.

RHEL The Listen directive specifies an IP address of 0.0.0.0, which is the same as not specifying an IP address, so Apache listens on all network interfaces. 

Listen 80

LoadModule

There are quite a few LoadModule directives (page ); these directives load the Apache DSO modules (page ).

Include

The Include directive (page ) includes the files that match *.conf in the /etc/httpd/conf.d directory, as though they were part of httpd.conf: 

Include conf.d/*.conf

Red Hat test page

When you first install Apache, there is no index.html file in /var/www/html; when you point a browser at the local Web server, Apache generates error 403, which returns the Red Hat test page. The mechanism by which this page is returned is convoluted: The Red Hat httpd.conf file holds an Include directive that includes all files in the conf.d directory that is in the ServerRoot directory (page ). The welcome.conf file in this directory contains an ErrorDocument 403 directive (page ) that redirects users who receive this error to error/noindex.html in the Document-Root directory (page ). The noindex.html file is the Red Hat test page that confirms the server is working but there is no content to display.

Section 2: Main Server Configuration

ServerAdmin, ServerName

As CentOS Linux is shipped, the ServerAdmin and ServerName directives are commented out. Change them to useful values as suggested in the ServerAdmin (page ) and ServerName (page ) sections.

DocumentRoot

The DocumentRoot directive (page ) appears as follows: 

DocumentRoot "/var/www/html"

You need to modify this directive only if you want to put your content somewhere other than /var/www/html.

<Directory>

The following <Directory> container (page ) sets up a restrictive environment for the entire local filesystem (specified by /): 

<Directory />
    Options FollowSymLinks
    AllowOverride None
</Directory>

The Options directive (page ) allows Apache to follow symbolic links but disallows many options. The AllowOverride directive (page ) causes Apache to ignore .htaccess files. You must explicitly enable less restrictive options if you want them, but be aware that doing so can expose the root filesystem and compromise system security.

Next another <Directory> container sets up less restrictive options for the DocumentRoot (/var/www/html). The code in httpd.conf is interspersed with many comments. Without the comments it looks like this: 

<Directory "/var/www/html">
    Options Indexes FollowSymLinks
    AllowOverride None
    Order allow,deny
    Allow from all
</Directory>

The Indexes option in the Options directive allows Apache to display directory listings. The Order (page ) and Allow (page ) directives combine to allow requests from all clients. This container is slightly less restrictive than the preceding one, although it still does not allow Apache to follow directives in .htaccess files.

DirectoryIndex

As explained on page , the DirectoryIndex directive causes Apache to return the file named index.php, index.html, index.htm, or index.shtml from a requested directory. Because Options Indexes is specified in the preceding <Directory> container, if none of these files exists in a queried directory, Apache returns a directory listing: 

DirectoryIndex  index.php index.html index.htm index.shtml

There are many more directives in this part of the httpd.conf file. The comments in the file provide a guide as to what they do. There is nothing here you need to change as you get started using Apache.

Section 3: Virtual Hosts

All lines in this section are comments or commented-out directives. If you want to set up virtual hosts, see page .