$re = '/^(?:ts(?:m(?:09|1[0-9]|20))?|edtd\-ts)\.eset\.com$/mi';
$str = 'tsm09.eset.com
tsm10.eset.com
tsm11.eset.com
tsm12.eset.com
tsm13.eset.com
tsm14.eset.com
tsm15.eset.com
tsm16.eset.com
tsm17.eset.com
tsm18.eset.com
tsm19.eset.com
tsm20.eset.com
ts.eset.com
edtd-ts.eset.com';
preg_match_all($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