php gets local ip or remote address

// 111111111111
echo $_SERVER['REMOTE_ADDR'];
// 2222222222222
function get_local_ip() {
    $preg = "/\A((([0-9]?[0-9])|(1[0-9]{2})|(2[0-4][0-9])|(25[0-5]))\.){3}(([0-9]?[0-9])|(1[0-9]{2})|(2[0-4][0-9])|(25[0-5]))\Z/";
//获取操作系统为win2000/xp、win7的本机IP真实地址
    exec("ipconfig", $out, $stats);
    if (!empty($out)) {
        foreach ($out AS $row) {
            if (strstr($row, "IP") && strstr($row, ":") && !strstr($row, "IPv6")) {
                $tmpIp = explode(":", $row);
                if (preg_match($preg, trim($tmpIp[1]))) {
                    return trim($tmpIp[1]);
                }
            }
        }
    }
//获取操作系统为linux类型的本机IP真实地址
    exec("ifconfig", $out, $stats);
    if (!empty($out)) {
        if (isset($out[1]) && strstr($out[1], 'addr:')) {
            $tmpArray = explode(":", $out[1]);
            $tmpIp = explode(" ", $tmpArray[1]);
            if (preg_match($preg, trim($tmpIp[0]))) {
                return trim($tmpIp[0]);
            }
        }
    }
    return '127.0.0.1';
}