A colleague of mine at Catapult Systems, Michael Rinner, recently sent out the below information to our team. This is a great new feature that prevents the need for many Autodiscover Certs and configurations.

I would like to share something I learned. I am currently doing a Hybrid configuration between Exchange 2010 SP3 and Exchange Online with approximately 50 SMTP domains. Previously, the hybrid configuration required an autodiscover record for each domain and a SAN certificate with autodiscover for each domain. Exchange 2013 and Exchange 2010 SP3 RU1 or later introduced an autodiscover domain feature. The autodiscover domain feature tells Exchange to use the autodiscover settings of the primary smtp domain for all domains.   http://technet.microsoft.com/en-us/magazine/dn249970.aspx

To make it work with the hybrid configuration wizard (HCW) do the following:

  1. Run the HCW with just the primary smtp domain and make sure it completes without any issues.
  2. Open the Exchange Management Shell from the hybrid server and run the following command.
    1. Set-hybridconfiguration –domains contoso.com, fabrikam.com, domaina.com, domainb.com autod:primarydomain.com (NOTE the autod) (Do not use quotes)
  3. Run the HCW again with all the domains populated.
  4. Then do a get-hybridconfiguration | fl and you should all the domains populated with the autod also.