Background info:

Ive got two Servers:

  • ServerA - Windows 2003 SBS Server, IP:, PDC for BizA.local, Exchange manages emails for BizA.com
  • ServerB - Windows Server 2010 with Exchange 2013, IP:, PDC for BizB.local, Exchange to manage emails for BizB.com.

Due to BTs network in the area, we are only able to get one static IP from them.

Due to the way the two companies work, they require access to both domains but need the option to be able to split the two domains if one company moves out of the office. All user accounts/permissions etc work fine.


I've got the emails for *@BizA.com being sent/received at ServerA no problems. Im trying to get the emails to income to ServerB for *@BizB.com. My plan was to point the MX record to the static IP (same as have done with *@BizA.com) and set up a Mail Relay from ServerA to ServerB.

Ive set ServerA to accept the *@BizB.com emails and this works, I get NDRs from the server saying The e-mail account does not exist at the organization this message was sent to. Check the e-mail address, or contact the recipient directly to find out the correct address. I've then created a new SMTP connector to relay the emails to ServerB. In theory, this should work but im not receiving any emails for *@BizB.com.

It may be something small and stupid that I've missed. Help would be appretiated.


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'Ive set ServerA to accept the *@BizB.com emails' - how?


If you use Exchange 2000 Server and Exchange Server 2003 on the Internet to accept e-mail for your main e-mail domain, you may want your Exchange 2000 Server and Exchange Server 2003 computers to also accept e-mail for another company (a company that your company just acquired, for example).

If you use the local e-mail domain microsoft.com and the non-local domain littlemicrosoft.com (for example), In Exchange 2000 Server and Exchange Server 2003, you create an SMTP connector to littlemicrosoft.com, and then click to select the allow messages to be relayed to this domain check box on the Address Space tab in the connector properties. The source bridgehead servers that you specify on the SMTP connector are the bridgehead servers that accept e-mail for this domain.

If you want another server to be the real bridgehead, create a "dummy" connector with a higher cost that is sourced on your inbound servers, and have the real path set at a lower cost.



Is it set as a relay domain or authoritative? It needs to be an External relay domain, otherwise it is looking for local mailboxes and will give you the error you are receiving.

Follow the guide here: http://demazter.wordpress.com/2010/02/26/configure-exchange-2007-or-2010-to-relay-email-for-an-additional-domain/

It will walk you right through it...

  • Im assuming that this would be done on ServerA? If this is the case, i cannot follow. Server A is Windows 2003 SBS, not 2k7/2010. – AdamL May 13 '14 at 13:00
  • Ah...sorry, my mistake, I'll modify the answer. If you have questions on how to accomplish the above, let me know. But it's pretty straightforward. – TheCleaner May 13 '14 at 13:37
  • To have ServerA accept the @BizB.com, I opened System Manager, expanded Recipients and then Recipent Policies, added a New policy and in the Email addresses tab, added @BizB.com When you mention *Create a SMTP connector, would you follow the steps here - support.microsoft.com/kb/265293 Ive followed these and was not able to send any outgoing emails, although emails from *@BizA.com addresses were received at ServerB, no emails from external sources though... – AdamL May 13 '14 at 14:12
  • Why did you add new email addresses for BizB.com on the SBS server? You shouldn't have done that unless you have existing BizA users that would need also require a BizB.com address (shared SMTP namespace...totally different thing). Remove that Recipient policy and make sure no BizB.com addresses exist for Recipients on BizA. And yes, that KB article on the connectors is the right one to follow. After you've removed the recipient policy you added, edit your question with screenshots of what you've set (just post them to imgur and post the URL and I can edit your question with actual pics). – TheCleaner May 13 '14 at 14:23
  • 1
    Yup, It was that tickbox. All working. I can now let me hair grow back. Many thanks for your help. – AdamL May 14 '14 at 10:54

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