$re = '/Area\[[^-]+-\s((?<optional>[^-]+)\s-)?(?<address>[^\]]+)/';
$str = 'Feb 14 14:44:18 exnet-01a.intechnologywifi.com local1 events: EventType[Area Change] MAC[00:B3:62:BE:8E:B7] Details: Area[SS1 - CCTV193 - Eastern Esplanade]
Feb 10 13:56:29 exnet-01a.intechnologywifi.com local1 events: EventType[Area Change] MAC[A4:E4:B8:6E:DD:D2] Details: Area[SS1 - Leigh On Sea Community Centre]';
preg_match_all($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