Hey Folks,

We have an AD domain (domaincorp.org) and also an Internet/email domain (domain.org). Our users have email addresses that employ the latter.

Recently, we have had need for an internal unix SENDMAIL relay to masquerade as user@domain.org . This seems to work fine when sending to external recipients. However, messages sent internally (to AD users) are dropped. However, the same message from the same SENDMAIL host succeeds when it originates as user@domaincorp.org .

We are running Exchange 2007 sp3 and both "domaincorp.org" and "domain.org" are listed in the "Accepted Domains" list at the origanization level, with domain.org being the default. Both hosts are on the same internal LAN . No DMZ, NAT'ing, etc. in play.

When sendmail IS NOT set to masquerade, both internal and external messages succeed. The relay/receive connector works perfectly. However the external RFC headers detect that the default domain of the unix box isn't SPX verified. When sendmail IS set to masquerading as domain.org, external succeeds and passes SPX muster. However, that same message now gets stopped cold internally. Nothing in message tracking even.

I should also add that the successful external messages to which I refer are routed thru a bulk mailserver and not the same Exchange box. So for the purposes of this thread, it is safe to say that ALL mail hitting the Exchange 2007 box itself is failing.

Our existing receive connector has "TLS, Basic, and Exchange" authentication methods set, and "Anonymous, Exchange Users, and Exchange Servers" for permission groups. SENDMAIL without masquerading succeeds to this connector, and an alternate connector.

How do I go about allowing mail from the internal relay to pose as user@domain.org?

Thanks!
Tom W.

Hi Tom,

Does this issue relate to Port?