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AutoDiscover and Two Domains

We have recently moved our sister company's email from their own SBS 2003 Exchange 2003 server to our SBS 2008 Exchange 2007 server. We have only moved their email and nothing else. They are still running as a separate domain from us except for their email. When trying to setup their Out Of Office replies they are unable to connect beacuse the "Server is unavailable". Everything else is fine and all their mail,contacts, etc. have been transferred over. My understanding is that the Autodiscover feature is necessary for them to succesfully use the OOF function. When I run the Exchange Connectivity test for Outlook AutoDiscover, it is failing for their domain while attempting to test the potential AutoDiscover URL at "https://sisterdomain.com/AutoDiscover/AutoDiscover.xml". The AutoDiscover functionality is working fine for our domain and all tests pass. It is my understanding that I have to add a record to their internal DNS to resolve "https://sisterdomain.com/AutoDiscover/AutoDiscover.xml" to our external IP address. Is this correct? Additionally, we have only one certificate that is setup for our domain and I am unsure as to whether I need to purchase a certifcate for their domain as well. I appreciate any help or advice on this matter. Please let me know if additional iformation is needed. Thank you.
1 Solution
Normally for the Outlook machines when connected to the AD
a) SCP will be tested and used
b) https://Emaildomain/autodiscover/autodiscover.xml 
c) https://autodiscover.emaildomain.com/autodiscover/autodiscover.xml will be tried
d) http of the b & c are tried
e) SRV record will be tried last.

So, in this case
The sister-domain client machines are connected to the Domain or not?
We need to have  a screen-shots of the "Test email autoconfiguration" results and log" tabs...to plan for the next query.
Apart from above, how are SBS2003 accounts linked to SBS2008 mailboxes? Linked mailboxes?

As a general guide, you are effectively deploying SBS2008 as a resource forest to SBS2003. It's worth having a look at a 3-part guide here:
Alan HardistyCommented:
As mentioned above (as a last resort) - the solution lies in adding an SRV record to the new domain's (your Sister companies) external DNS records that points to an FQDN that is included in your SSL certificate e.g., www.yourdomain.com / mail.yourdomain.com

Adding an SRV record will then point their domain to your domain and resolve happily and make Autodiscover work for them.

The details you will need to add an SRV record are:

Service: _autodiscover
Protocol: _tcp
Priority: blank
Weight: 100
Port: 443
Result: www.yourdomain.com or mail.yourdomain.com (whatever name is included in your SSL certificate)

Some reading from Microsoft:


This is how you can host multiple domains on a 5-name SSL certificate without having to add each and every domain to the certificate, which can be extremely costly.  If you follow the above advice, you won't need to buy a new SSL cert.
Creating Active Directory Users from a Text File

If your organization has a need to mass-create AD user accounts, watch this video to see how its done without the need for scripting or other unnecessary complexities.

ctsuhakoAuthor Commented:
Sorry for the delay in responding. The SRV record should be added to the external DNS and not the internal DNS? Thank you.
Alan HardistyCommented:
Yes - correct.  External DNS.
ctsuhakoAuthor Commented:
Thank you. I have told them to make the change. I will let you know how it works out.
Alan HardistyCommented:
No problems.  It should be fine one it resolves happily - but only time will tell, so give it 24-48 hours and test it periodically.
ctsuhakoAuthor Commented:
Worked perfectly! Thank you.
Alan HardistyCommented:
Excellent.  Thanks for the points.


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