$re = '/access-list.*\b(?<src>\d+\.\d+\.\d+\.\d+).*\-\>.*\b(?<dst>\d+\.\d+\.\d+\.\d+)/';
$str = '2011-04026T19:10:17-06:00 ant-fw : %ASA-4-106023: Deny tcp src inside:192.1.1.102/3191 dst outside:204.1.1.28/443 by access-group "inisde" [0x0,0x0]
2011-04026T19:28:24-06:00 ant-fw : %ASA-4-106100: access-list dmz permitted udp dmz/10.1.1.20(123) -> outside/91.1.1.4(123) hit-cnt 1 first hit [0x7f55f1d2, 0x0]
';
preg_match_all($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