$re = '/^(?:[4-9]|\d\d+)(?:\.\d+){3}|3\.[2-9]\d(?:\.\d+){2}|3\.1[1-9](?:\.\d+){2}|3\.10\.[1-9]\d?\.\d+$/m';
$str = '3.10.1.0
3.10.2.0
3.10.13.1
3.11.0.0
3.11.2.0
3.20.0.0
4.0.0.0
5.0.0.0
10.0.0.0
3.10.0.0
3.9.0.0
3.1.0.0
3.0.0.0
2.0.0.0
1.0.0.0';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php