使用DKIM配置phpmailer

Question

我按照本教程在服务器上安装了DKIM： http://www.howtoforge.com/set-up-dkim-domainkeys-identified-mail-working-with-postfix-on-centos-using-opendkim

然而，phpmailer希望以下字段使用DKIM：

/**
* Used with DKIM DNS Resource Record
* @var string
*/
public $DKIM_selector   = '';

/**
 * Used with DKIM DNS Resource Record
 * optional, in format of email address 'you@yourdomain.com'
 * @var string
*/
public $DKIM_identity   = '';

/**
 * Used with DKIM DNS Resource Record
 * @var string
 */
public $DKIM_passphrase   = '';

/**
 * Used with DKIM DNS Resource Record
 * optional, in format of email address 'you@yourdomain.com'
 * @var string
 */
public $DKIM_domain     = '';

/**
 * Used with DKIM DNS Resource Record
 * optional, in format of email address 'you@yourdomain.com'
 * @var string
 */
public $DKIM_private    = '';

我知道选择器和私钥。但密码是什么？

另外，对于identy，我可以放*@mydomain.com吗？