$re = '/(192\.168\.(1|2|10|11|12|20|21|22)\..+)|(10\.0\.0\.99)|(172\.0\.0\.45)|(172\.0\.0\.46)|(10\.10\.10\.50)|(10\.10\.10\.52)/m';
$str = '192.168.189.999
192.168.22.3
192.168.10.10
192.168.1.1
10.0.0.99
10.10.10.50
10.10.10.51
10.10.10.52
10.10.10.53
';
preg_match_all($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