MonitorWare Knowledge Base

Hello!

I have an AD network (domain1.com[10.10.10.x]). My mailserver is hosted outside this network (mail.domain1.com [216.xxx.xxx.xxx]).
Email sent to external recipients delivers fine, as it is routed through mail.domain1.com. However if I try to send a message from user@domain1.com to user2@domain.com it does not get delivered. -- It never even gets to the mail server outside the network.

Logic tells me that outlook is trying to be smart to route the mail, does a dns query of my AD server, and that shows domain1.com to be ip 10.10.10.10 (internal server), rather than sending the mail through the mail server that is external.

Question is this: How do I add a DNS record (or something else) to force all mail to go through the external server? Help is much appreciated!

This problem always appears if you use your external domain name also as the AD DNS name. In fact, I recommend to use a different name (e.g. internal.example.com) for that purpuse, that'll save you the hassle.

OK, can't be done now in this case (at least not with reasonable effort). As such, you need to mirror all those external records pointing to Mail and Web servers to the internal one. I suggest that you look at your external DNS and make sure that the MX and A (and eventually CNAME and others) will be carried over to the internal domain. You can use DNS admin to create the new records. As far as the original problem (failed mail delivery) is concerned, you are probably in need of the MX records as well as the A records which help resolve the names of the mail servers.

... one important point: be sure to (manually) update those records whenever the external DNS changes

HTH
Rainer