Changes

*[http://linuxmanpages.com/man8/dhcpd.8.php dhcpd]

*[http://linuxmanpages.com/man5/dhcpd.conf.5.php dhcpd.conf]

*[http://linuxmanpages.com/man5/dhcp-options.5.php dhcpd-options]

*[http://www.linuxcertif.com/man/1/systemctl/ systemctl]