I had Comcast create a reverse dns entry for our mail server's static IP.
However, it does not resolve correctly.
Hello smsschulz and welcome,
Per the following DNSGoodies provided information I do not believe exchange.mydomain.com is a valid personalized enough domain name:
As you can see there is no zone file records contained with this domain name. Please look into obtaining a more personalized domain name for your mail server and then the correct Reversed DNS can be provided.
Hope this helps you out.