$re = '/^$|^(http(s)?:\/\/([a-zA-Z0-9.-]*)(:\d{0,5})?,?)*$/m';
$str = 'http://192.168.1.100:32400,http://192.168.1.100:32400,http://sasdfds.com
http://sasd-fds.com
http://GASGH-ASD.com
https://sasd-fds.test.long.com
http://192.168.1.100:32400
https://192.168.1.100:32400
http://adomain.com:32400
https://adomain.com:32400
https://192.168.1.100:32400
http://adomain.com:32400
https://adomain.com:32400
';
preg_match_all($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