Based on the answer and research by Ben D...
# Get the URL from the GET Parameters
$url = $_GET['d'];
# Derive the HTTP Host
$hostname = parse_url( $url , PHP_URL_HOST );
# Strip the "WWW." from the hostname if present
$hostname = preg_replace( '/^www\./i' , '' , $hostname );
# Look for the IP Address
$ip_address = gethostbyname( $hostname );
if( filter_var( $hostname , FILTER_VALIDATE_IP ) ){
echo 'Hostname is an IP Address already';
echo $hostname;
}elseif( $ip_address==$hostname || $ip_address=='67.215.65.132' ){
echo 'Domain Not Found';
}elseif( filter_var( $ip_address , FILTER_VALIDATE_IP ) ){
echo $ip_address;
echo $hostname;
}else{
echo 'Invalid IP Address Returned';
echo $ip_address;
echo $hostname;
}