Mail Server

Mail Server
When one first tackles the scheme of getting Internet mail delivered to their mail system, you are very quickly pointed to the need for getting an Mx article published within your domain's public Dns zone. It is this article that tells all of the other mail servers on the planet where to route email destined for your domain.
Mail Server

What most do not tell you is the point of getting both the forward (A record) and reverse (Ptr record) Dns entries right for the server that is the send connector. In some cases this is the same server as the receive connector, but it does not need to be. It is very foremost that any server that is configured as an Internet Send Connector have both a forward (A record) and reverse (Ptr record) published in Dns, and that these records exactly match what you have entered in the Fqdn field on the general tab of your Send Connector. If this one server is hosting both the send and receive connectors, the Mx article should also point to this same name. If your society accepts mail for more than one domain, plainly point the Mx article in each domain to the same Fqdn. There is no requirement that an Mx article point to a server in the same Dns domain as the Mx record.