$re = '/:\d\d\s+(?:\d+\s+|(?:user|daemon|local.?)\.\w+\s+)*\[?(\w[\w\.\-]{2,})\]?\s/m';
$str = '2019-08-05 19:44:06 6 192.168.1.245 - - 192.168.1.239 192.168.1.239 Unavailable - policy_denied DENIED "Technology/Internet" 403 TCP_DENIED GET - https settings-win.data.microsoft.com 443 - "MSDW" 192.168.1.239 1534 355 - none - - high settings-win.data.microsoft.com "Technology/Internet" unavailable unavailable';
preg_match_all($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