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<title>Starting Apache</title>
<summary>
<p>On Windows, Apache is normally run as a service on Windows
NT, or as a console application on Windows 95. For details, see
<a href="platform/windows.html#run">running Apache for
Windows</a>.</p>
<p>On Unix, the <a href="programs/httpd.html">httpd</a> program
is run as a daemon that executes continuously in the
background to handle requests. This document describes how
to invoke <code>httpd</code>.</p>
</summary>
<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 first thing that <code>httpd</code> 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/apache/bin/httpd -f
/usr/local/apache/conf/httpd.conf</example>
<p>As an alternative to invoking the <code>httpd</code> binary
directly, a shell script called <a
href="programs/apachectl.html">apachectl</a> is provided which
can be used to control the daemon process with simple commands
such as <code>apachectl start</code> and <code>apachectl
stop</code>.</p>
<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 <code>httpd</code> or
<code>apachectl</code> 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. The <code>apachectl</code> script is
designed so that it can often be linked directly as an init
script, 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 <a
href="programs/httpd.html">httpd</a> and <a
href="programs/apachectl.html">apachectl</a> 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>