Exchange 2010 Handoff to External Server

Question

Ok so I'm going to explain the situation before I actually ask my question. I have two mail servers set up. One is setup for websites to use and the other is an exchange system which is the main mail system for the domain name i'm using.

Both work fine independently, however what I'd like to do, is have Exchange hand off any email address that doesn't exist in it, to a second server for processing, and if the email doesn't work on that server, it would send the rejection notice.

For example:

user1@domain.tld exists on the exchange server, so it would be directed there.
support@domain.tld doesn't exist on the exchange server but it does exist on the second mail server.

I've tried this using DNS, and I've looked into using SMTP Connectors, nothing seems to be working. It would be beneficial to have both servers working as I need one for the website to function properly and it does not work with exchange, but I don't want the emails sent from a domain that is not ours (it will confuse customers). Is there a more simple way to do this?

Someone please enlighten me. :)

* UPDATE * I created a receive connector in exchange, and it worked for about 10 minutes, then it stopped working. So I believe I'm heading in the correct direction.

Answer 1

You can try the following:

• configure your domain at exchange as type "internal relay": Set-AcceptedDomain -identity "domainname" -DomainType "InternalRelay"
• configure your local DNS server to return the MX record for your accepted domain with the external mailserver
• let the mx record point to your exchange server

this should get you:

internal mails between exchange accounts are locally delivered external mails to exchange accounts are delivered to their mailboxes external mails to non existent accounts are delivered via local dns to the external mailserver and ndr are generated if the address does not exist.

also if you can't configure the local dns server you cant ry to configure an catchall-address and forward all catched emails to an mailcontact with an address from the other mailserver configured. (http://technet.microsoft.com/en-us/library/bb691132(v=exchg.141).aspx)