$re = '/^([0-1]\d|2[0-4])\:[0-5]\d:[0-5]\d$/mi';
$str = 'afd26bsh377777777777777
192.168.4567.
.com@napier.co.uk
13:22:59
04:24:45
35:27:48
26:34:34
13:56:53
16:59:23
00:00:00:21:23:12
';
preg_match_all($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