A. Yes. Vaultastic supports a wide range of mail servers such as Zimbra, MS Exchange, Lotus Domino, MDaemon, Postfix etc.
You can configure a forwarding or journaling feature of the primary mail server to secure a copy of every incoming and outgoing mail to Vaultastic.
This ensures that you have a read only and tamper proof copy of every mail on the AWS cloud that can be accessed by end users using the self service portal.