From: Sandy Pratt on
I'm struggling to understand how to fix a problem with SBS 2003 Exchange
using ISA server.

We are company AA and, together with three other businesses (ie companies
BB, CC and DD), we have just purchased company XX. Each company uses
different ISPs.

At company AA, we need to be able to send email outbound from our Exchange
2003 server as both Sandy(a) and Sandy(a) I've set up each user in
the Active Directory with email addresses for both domains and made
the primary address for each user. The SBS configuration is set up with
company AA as the primary domain for Active Directory and Exchange. The SBS
Exchange 2003 server uses SMTP for outgoing email and POP3 for incoming.
This all works fine.

The IT support guy at company XX has changed the settings on his Linux
server so that all incoming email to Sandy(a), John(a), Sally etc are forwarded to Sandy(a), John(a), Sally(a) etc at
the other ISPs. That works fine. When any one mail recipient at company
BB receives an incoming email it is correctly forwarded to company AA. When
John at company BB sends an email to me at Sandy(a) with a copy to
Sally(a) the server correctly forwards all the email to me at companies
AA and Sally at company CC.

The problem we have is that, once the Exchange server in company AA has
received the forwarded email from John, it tries to send a copy to the
other recipients. This seems to create some kind of circular messaging
resulting in the following NDR:

Your message did not reach some or all of the intended recipients.

Subject: New Business at VS
Sent: 22/09/2005 11:29

The following recipient(s) could not be reached:
Sally Simpson on 22/09/2005 11:35

There was a SMTP communication problem with the recipient's email
server. Please contact your system administrator.
< #5.5.0 smtp;550 John(a)>... Not permitted

I've checked that we are not a relay and we are not blacklisted.
At company AA, our Active Directory has been set up with a new
Organisational Group containing contact records for John, Sally etc. Each
contact record has an primary email address of, for example John(a) and
a secondary email address of John(a)BB. The company AA Exchange server has a
default recipient policy with the company AA domain set as "responsible for
all incoming mail". I've set up a higher priority recipient policy for
incoming mail for company XX domain recipients. Do I need to check the box
for "this Exchange Organization is respnxible for all mai delivery to this
address"? What else do I need to do to stop these NDRs?