On the 2.4.x branch:

    <status>Extension</status>

    <sourcefile>mod_md.c</sourcefile>

    <identifier>md_module</identifier>

    <compatibility>Available in version 2.5.0 and later</compatibility>

    <compatibility>Available in version 2.4.30 and later</compatibility>

    <summary>

        <p>

        This module manages common properties of domains for one or more virtual hosts. 

    DocumentRoot htdocs/a

    SSLEngine on

    # no certificates specification needed!

    # no certificates specification

</VirtualHost>

        </highlight>

        <p>

        </p>

        </note>

        <note><title>Prerequisites</title>

        <p>

            This module requires <module>mod_watchdog</module> to be loaded as well.

        </p><p>

            Certificate signup and renewal with Let's Encrypt requires your server to be

            reachable on port 80 (http:) from the outside. The alternative method over

            port 443 (https:) is currently disabled for security reasons (status from

            2018-01-14).

        </p><p>

            The module will select from the methods offered by Let's Encrypt. If LE decides

            at one point in the future, to re-enable it again, <module>mod_md</module> will

            use it when suitable.

        </p><p>

            But for now, only the port 80 variant is available (termed "http-01"). Only

            when LE can reach your server on port 80 will <module>mod_md</module> work for

            you. For now, at least.

        </p><p>

            If you do not want to offer any sites on port 80 any more, you may leave it open

            and redirect all requests to your https: sites instead. Use the

            <directive module="mod_md">MDRequireHttps</directive> described below to do

            that in a convenient fashion. This will continue to answer http: challenges

            from Let's Encrypt. 

        </p>

        </note>

    </summary>

    <directivesynopsis>