$re = '/^[a-fA-F0-9]{2}(?:[:-]?[a-fA-F0-9]{2}){5}(?:,[a-fA-F0-9]{2}(?:[:-]?[a-fA-F0-9]{2}){5})*$/m';
$str = '12aeabc11bba,662baea1abc2
12-ae-ab-c1-1b-ba,66-2b-ae-a1-ab-c2
12:ae:ab:c1:1b:ba,66:2b:ae:a1:ab:c2
12aeabc11bba,662baea1abc2
';
preg_match_all($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