Here is my situation: I have been hosting the website and mail for a local car dealership. The manufacturer (GM) is forcing the dealerships to a common website platform hosted by a single company named Cobalt, but they only host the website, not the email. The dealership wants my company to continue hosting the mail with the same domain name as before. Cobalt's support will only communicate with the dealership in writing. I need to have the dealership tell Cobalt support specifically how to modify the DNS records so that the email routes to my server. So, do I need to have the A record for Mail modified to point at my servers IP, or do I need to have the MX record modified to point at mail servers domain name? Or a combination of the two? I am fuzzy on how it should be done since there is both a Mail A record, and a Mail MX record? When do you use which, or both?