I have users complaining more frequently about email that's not leaving the queue. When I look into the problem, it seems the destination has no MX record, just a host record. Message delivery is set to use DNS. I usually get around it by setting up a static rule to forward these domains to another mail server, but it's happening more and more and I'd like to get ahead of the problem (it's also not easy to explain the cause to end users, they just chant "the email is down"). These are all public severs usually hosted by some ISP, and all have been child domains (x.y.com). Should my mail server try to forward to a mail server in the parnt domain (y.com) if there is no MX record in the child? Is there a way to configure Exchange 5.5 send mail to servers that do not have MX entries without defining the specific domain? If so, will it cause any other problems?