DirectAdmin use port 80

1. create a da.ns64.small-dns.net account first, enable SSL, use private_html

2. add /usr/local/directadmin/data/users/dans72/http.conf
        SSLProxyEngine ON
        ProxyRequests Off
        ProxyPass / https://localhost:2222/
        ProxyPassReverse / https://localhost:2222/

3. vi /usr/local/directadmin/conf/directadmin.conf
check_referer=0

4. restart apache