Exchange 2010 relay through Exchange 2003 to external addresses

Hi, I have just installed a new Exchange 2010 box in our network which has an Exchange 2003 server. The 2010 box sends through a connector via the 2003 box.

From a mailbox on the 2010 Server, I am able to send mails internally. I cannot send to external addresses.

I have added the 2010 IP addresses to the 2003 Virtual SMTP Server Relay Restrictions list (allowed).
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Are you getting any NDR's back?  What information is message tracking showing?
dcsl_supportAuthor Commented:
Here is my NDR - message tracking is on, what do I look for:

Delivery has failed to these recipients or groups: (
A problem occurred during the delivery of this message to this e-mail address. Try sending this message again. If the problem continues, please contact your helpdesk.

The following organization rejected your message: w2k3server1.internal.local.

Diagnostic information for administrators:
Generating server: EXCHANGE1.internal.local
w2k3server1.internal.local #550 ######## INVALID RECIPIENT ######## ##
Original message headers:
Received: from EXCHANGE1.internal.local ([fe80::412b:40d1:4c9d:f7d3]) by
 Exchange1.internal.local ([fe80::412b:40d1:4c9d:f7d3%11]) with mapi; Wed, 24
 Mar 2010 08:37:22 +0000
From: dcslAdmin <>
To: "" <>
Subject: test
Thread-Topic: test
Thread-Index: AcrLLThbfqYq7LHSTR63jT8q1bL29A==
Date: Wed, 24 Mar 2010 08:37:21 +0000
Message-ID: <A2A8AA37C848AB4F969F393F07E1D2016993@Exchange1.internal.local>
Accept-Language: en-GB, en-US
Content-Language: en-GB
Content-Type: multipart/alternative;
MIME-Version: 1.0
Have you made any changes to your DNS in the last 30 to 60 days? Make sure the Exchange server is pointing to the correct DNS server.
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dcsl_supportAuthor Commented:
No changes to DNS. Exchange1 points to the local DNS server.

This is a brand-new 2010 box and I have just moved a mailbox over and tried to send mail externally. I'm sure it's something to do with Relay permissions.

Note that I have IP V6 enabled.
In your smtp connector do you have the w2k3 connector specified as the local bridge head server?
dcsl_supportAuthor Commented:
Yes, I do.
dcsl_supportAuthor Commented:
Nope, doesn't look like that will help. Thanks anyway.
dcsl_supportAuthor Commented:
I've found the issue. We are using Exclaimer Anti-spam and I have to remove the tick in the anti-spam rules for "Recipient not in AD".

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