Our AD domain is ad.domain.com and our email uses the top level domain of domain.com. However when a user sends an email to user1@ad.domain.com it eventually bounces back with a delivery failed message after a few days of retrying. When an email is sent to user1@new.domain.com (which is not setup anywhere in exchange or DNS) it immediately bounces back.
Domain.com is set as the accepted domain for exchange as well. I'm assuming that because our active directory domain is ad.ccrsb.ca that the system thinks its a valid mail domain and tries to send mail to it. I'm wondering if anyone knows a way
to have email sent to @ad.domain.com to immediately bounce back to the user just like sending to another invalid mail domain. We don't want email sent to ad.domain.com to go through to the users at all because that will not stop users from sending to
the bad addresses.
Thanks in advance,
Matt