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<title>Starting Apache</title>

<summary>

<p>On Windows, Apache is normally run as a service on Windows

NT, 2000 and XP, or as a console application on Windows 9x and

ME. For details, see <a

href="platform/windows.html#winsvc">Running Apache as a Service</a>

and <a href="platform/windows.html#wincons">Running Apache as a

Console Application</a>.</p>

<p>On Unix, the <program>httpd</program> program

is run as a daemon that executes continuously in the

background to handle requests. This document describes how

to invoke <program>httpd</program>.</p>

</summary>

<seealso><a href="stopping.html">Stopping and Restarting</a></seealso>

<seealso><program>httpd</program></seealso>

<seealso><program>apachectl</program></seealso>

<section id="startup"><title>How Apache Starts</title>

<p>If the <directive module="mpm_common">Listen</directive>

specified in the configuration file is default of 80 (or any other

port below 1024), then it is necessary to have root privileges in

order to start apache, so that it can bind to this privileged

port. Once the server has started and performed a few preliminary

activities such as opening its log files, it will launch several

<em>child</em> processes which do the work of listening for and

answering requests from clients. The main <code>httpd</code>

process continues to run as the root user, but the child processes

run as a less privileged user. This is controlled by the selected

<a href="mpm.html">Multi-Processing Module</a>.</p>

<p>The recommended method of invoking the <program>httpd</program>

executable is to use the <program>apachectl</program> control script. This

script sets certain environment variables that are necessary for

<program>httpd</program> to function correctly under some operating

systems, and then invokes the <program>httpd</program> binary.

<program>apachectl</program> will pass through any command line

arguments, so any <program>httpd</program> options may also be used with

<program>apachectl</program>. You may also directly edit the

<program>apachectl</program> script by changing the <code>HTTPD</code>

variable near the top to specify the correct location of the

<program>httpd</program> binary and any command-line arguments that you

wish to be <em>always</em> present.</p>

<p>The first thing that <program>httpd</program> does when it is

invoked is to locate and read the <a

href="configuring.html">configuration file</a>

<code>httpd.conf</code>. The location of this file is set at

compile-time, but it is possible to specify its location at run

time using the <code>-f</code> command-line option as in</p>

<example>/usr/local/apache2/bin/apachectl -f

/usr/local/apache2/conf/httpd.conf</example>

<p>If all goes well during startup, the server will detach from

the terminal and the command prompt will return almost

immediately. This indicates that the server is up and running.

You can then use your browser to connect to the server and view

the test page in the <directive

module="core">DocumentRoot</directive> directory

and the local copy of the documentation linked from that

page.</p>

</section>

<section id="errors"><title>Errors During Start-up</title>

<p>If Apache suffers a fatal problem during startup, it will

write a message describing the problem either to the console or

to the <directive module="core">ErrorLog</directive> before

exiting. One of the most common error messages is "<code>Unable

to bind to Port ...</code>". This message is usually caused by

either:</p>

<ul>

<li>Trying to start the server on a privileged port when not

logged in as the root user; or</li>

<li>Trying to start the server when there is another instance

of Apache or some other web server already bound to the same

Port.</li>

</ul>

<p>For further trouble-shooting instructions, consult the

Apache <a href="faq/">FAQ</a>.</p>

</section>

<section id="boot"><title>Starting at Boot-Time</title>

<p>If you want your server to continue running after a system

reboot, you should add a call to <program>apachectl</program> to your

system startup files (typically <code>rc.local</code> or a file in

an <code>rc.N</code> directory). This will start Apache as

root. Before doing this ensure that your server is properly

configured for security and access restrictions.</p>

<p>The <program>apachectl</program> script is designed to act like a

standard SysV init script; it can take the arguments

<code>start</code>, <code>restart</code>, and <code>stop</code>

and translate them into the appropriate signals to

<program>httpd</program>. So you can often simply link

<program>apachectl</program> into the appropriate init directory. But be

sure to check the exact requirements of your system.</p>

</section>

<section id="info"><title>Additional Information</title>

<p>Additional information about the command-line options of <program>

httpd</program> and <program>apachectl</program> as well as other support

programs included with the server is available on the

<a href="programs/">Server and Supporting Programs</a> page.

There is also documentation on all the <a

href="mod/">modules</a> included with the Apache distribution

and the <a href="mod/directives.html">directives</a> that they

provide.</p>

</section>

</manualpage>