Hello all

I am running Exchange 2013 Ru8. I host many different smtp domains. Example "abc.com" "cbs.com"
and "123.com". some users have "@123.com" stamped as a secondary smtp address.  Autodiscover.123.com and mail.123.com resolve externally to the public ip address on the firewall. As a test i created "autodiscover.abc.com" and "autodiscover.cbs.com" A records in external DNS and pointed these two records to the external ip address on our firewall. We currently use a wildcard cert on the Exchange servers   "*.123.com".  I'm noticing if a user connects remotely and has a primary SMTP address of @abc.com or @cbc.com and they have a secondary smtp address of "@cbs.com"  they do not get a certificate prompt warning that the name doesn't match. However if a user is running outlook 2010 they do get a certificate warning prompt.

From everything that i understand about Autodiscover process, is that the autoD process will always use the users primary email address to construct the Autopdiscover request.  If this is true then i would have expected the users who's primary email address is @abc.com or @cbs.com, but have a secondary email address of @123.com  to get a certificate warning, however the 2013 users get no warning at all, but the 2010 users do. 

do the two different client versions handle autodiscover  process differe

Hi,

Based on my knowledge, there is no difference for autodiscover service between Outlook 2013 and Outlook 2010.

Please confirm whether the issue happens to all Outlook 2010 users. Also check the Autodiscover service in client side by running Test E-mail AutoConfiguration tool:

Open Outlook - press CTRL key - right click on the Outlook icon from right bottom corner taskbar - Test Email AutoConfiguration. Put your email address - uncheck use guessmart and secure guessmart authentication - click Test to check your Autodiscover service.

And collect the Logs tab and Results tab information to check your mismatch namespace.

In Exchange server, please run the following command to check your certificate settings:

Get-ExchangeCertificate | fl

Please share the information here for more help.

Regards,