I am in the process of point to a exteral mail server. I was hosting my own exchange system in house but I am in the process of switching over to an external mail client. My DNS would point to the internal mail exchange mail.hchd.us but the new external mail client uses the same name mail.hchd.us. When I ping internally it will ping back the internal ip address which is not what I want. How to I clearn out the old mail exchange to point to the external mail client.