The organization responsible for our mail infrastructure has recently embarked upon a migration to Microsoft Exchange. The group I work with has encountered some problems with the Exchange implementation. Because there are political issues involved here as well as the technical ones, I'm looking for a little help understanding how Exchange operates before I go to the IT folks.
Exchange is currently hosting the
example.com subdomain. We have applications on hosts within this domain that expect to receive email directly. Due the local mail routing infrastructure, email from outside of our organization to, for example,
user@machineA.example.com works just fine...but mail sent to the same address from within the Exchange environment bounces with the following error:
#554 5.4.4 SMTPSEND.DNS.NonExistentDomain; nonexistent domain ##
This happens regardless of whether or not there exists an
MX record for the target host. It appears that Exchange believes that it is unilaterally responsible for both
example.com and all subdomains thereof.
Is this fundamental to the behavior of Exchange? Is there a way to configure Exchange so that it Does The Right Thing according to RFC2821, even for subdomains of the domain for which it is the primary mailserver?