I don't know if this is an issue or not, but let me explain my situation and maybe someone can tell me if there could be any issues:
Our domain (FQDN) is mack.com. When the email server was set up, the owners wanted email to go to stars.com rather than the mack.com.
Now the exchange server is on the mack.com domain and has an A record in the local DNS as exchange.mack.com with the correct IP for that server. A second lookup zone was created called stars.com with an A record pointing to mail.stars.com and an MX record pointing to exchange.mack.com.
When I do an nslookup and set the type to MX, I show the following:
primary name server = dc1.mack.com (which is our domain controller)
responsible mail addr = admin.mack.com
serial = 3126
refresh = 900
retry = 600
expire = 86400
default TTL = 3600
That's it. It doesn't show the MX records or anything else.
We have various small email issues, such as php mailing scripts not being sent on by the email server (but not kicking any errors), dropped emails to external customers, failure to receive emails from some customers (also with no error returns to either side).
Don't know much about DNS so I'm just trying to figure out if this type of dual FQDN like what we have could be causing any issues.
Thank you for your time.