Outlook certificate warning for Exchange servers FQDN

We are in the process of migrating from Exchange 2010 to Exchange 2013 and have the following setup:

- 1 Ex2010 server:
  sola-exchange.addomain.local
- 3 Ex2013 servers set up in a DAG:
  sola-ex13-1.addomain.local, sola-ex13-2.addomain.local, sola-ex13-3.addomain.local
- Split DNS with all Virtual Directorys set with the same internal and external hostnames in URL:
  webmail.domain.com, oa.domain.com, eas.domain.com, autodiscover.domain.com.
- DNS round-robin for the above domain names pointing to each of the 2013 server IPs
- Wildcard certificate *.domain.com
- NTLM authentication for Outlook Anywhere, the CertPrincipleName has been set to msstd:*.domain.com

The problem:
Everything seems to work as it should, but users are presented with a certificate warning 20 or so seconds after opening Outlook.
Example: When I open Outlook I get a warning that the certificate name does not correspond with the name of the server. It tries to connect to "sola-ex13-3.addomain.local" and the certificate is the wildcard *.domain.com.
An other user might get the same warning but for an other server FQDN, sola-ex13-2.addomain.local.

This does not happen when connecting externally. Published with a TMG server.

Why does Outlook try to connect to a servers FQDN when al the virtual directory URLs are set?

March 11th, 2015 7:27am

This is because Outlook detected the autodiscover service connection point (SCP) in AD.

To resolve this problem,

get-clientaccessserver | set-clientaccessserver -autodiscoverserviceinternaluri https://autodiscover.domain.com/autodiscover/autodiscover.xml

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March 11th, 2015 8:46am

This is because Outlook detected the autodiscover service connection point (SCP) in AD.

To resolve this problem,

get-clientaccessserver | set-clientaccessserver -autodiscoverserviceinternaluri https://autodiscover.domain.com/autodiscover/autodiscover.xml

March 11th, 2015 8:46am

Hi,

Please change your internal URLs to the same as your external URLs namespace. For example: Webmail.domain.com.

Set-ClientAccessServer -Identity CAS_Server_Name -AutodiscoverServiceInternalUri https://webmail.domain.com/autodiscover/autodiscover.xml
Set-WebServicesVirtualDirectory -Identity "CAS_Server_Name\EWS (Default Web Site)" -InternalUrl https://webmail.domain.com/ews/exchange.asmx
Set-OABVirtualDirectory -Identity "CAS_Server_name\oab (Default Web Site)" -InternalUrl https://webmail.domain.com/oab

For detailed steps about it, please refer to:

https://support.microsoft.com/kb/940726?wa=wsignin1.0

Regards,

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March 12th, 2015 7:27am

Thank you for your proposals.

Li: The AutoDiscoverServiceInternalUri has allready been set to https://autodiscover.domain.com/Autodiscover/Autodiscover.xml for all servers.

Winnie: These are allready OK.

Get-WebServicesVirtualDirectory | fl Name,AutoDiscoverServiceInternalUri
Name                           : SOLA-EX13-2
AutoDiscoverServiceInternalUri : https://autodiscover.domain.com/Autodiscover/Autodiscover.xml
Name                           : SOLA-EX13-3
AutoDiscoverServiceInternalUri : https://autodiscover.domain.com/Autodiscover/Autodiscover.xml
Name                           : SOLA-EX13-1
AutoDiscoverServiceInternalUri : https://autodiscover.domain.com/Autodiscover/Autodiscover.xml

Get-OabVirtualDirectory | fl Server,*Url
Server      : SOLA-EX13-2
InternalUrl : https://oa.domain.com/OAB
ExternalUrl : https://oa.domain.com/OAB
Server      : SOLA-EX13-3
InternalUrl : https://oa.domain.com/OAB
ExternalUrl : https://oa.domain.com/OAB
Server      : SOLA-EX13-1
InternalUrl : https://oa.domain.com/OAB
ExternalUrl : https://oa.domain.com/OAB

March 12th, 2015 8:20am

Thank you for your proposals.

Li: The AutoDiscoverServiceInternalUri has allready been set to https://autodiscover.domain.com/Autodiscover/Autodiscover.xml for all servers.

Winnie: These are allready OK.

Get-WebServicesVirtualDirectory | fl Name,AutoDiscoverServiceInternalUri
Name                           : SOLA-EX13-2
AutoDiscoverServiceInternalUri : https://autodiscover.domain.com/Autodiscover/Autodiscover.xml
Name                           : SOLA-EX13-3
AutoDiscoverServiceInternalUri : https://autodiscover.domain.com/Autodiscover/Autodiscover.xml
Name                           : SOLA-EX13-1
AutoDiscoverServiceInternalUri : https://autodiscover.domain.com/Autodiscover/Autodiscover.xml

Get-OabVirtualDirectory | fl Server,*Url
Server      : SOLA-EX13-2
InternalUrl : https://oa.domain.com/OAB
ExternalUrl : https://oa.domain.com/OAB
Server      : SOLA-EX13-3
InternalUrl : https://oa.domain.com/OAB
ExternalUrl : https://oa.domain.com/OAB
Server      : SOLA-EX13-1
InternalUrl : https://oa.domain.com/OAB
ExternalUrl : https://oa.domain.com/OAB

Hi,

Sorry for my delay. Has the issue been resolved?

Please run the following command to get detailed certificate information in your Exchange server:

Get-ExchangeCertificate | fl

In client side, pease run the Test E-mail AutoConfiguration tool to confirm which service is used with the mismatch namespace:

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. Collect the inofrmation in the Results tab.

Regards,

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March 20th, 2015 1:23am

Hi,

Any updates?

Regards,

March 23rd, 2015 9:26pm

I'm battling this exact issue.

I'm curious, do you have the EXCH outlook provider CertPrincipal name set?

Get-OutlookProvider

It is typical with wildcard certs to set the EXPR provider. But I'm finding I may also need to set the EXCH provider.

Set-OutlookProvider EXCH -CertPrincipalName msstd:*.domain.com
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May 25th, 2015 3:48pm

Hi,

Sorry for the late reply!

I'm not sure why, but this problem has gradually resolved itself. Must have been because of other changes/fixes we have had to perform during our migration.

We are using a wildcard cert, and I had only set the EXPR provider with CertPrincipalName msstd:*.domain.com.
A few days ago we had problems with some Outlook 2007/2010 users after we moved them to Exchange 2013.
I had noticed that the OA settings in Outlook was AutoDiscovered to msstd:oa.domain.com, but it worked fine both internal and external with Outlook 2010/2013 during testing.
I found that manually changing to msstd:*.domain.com on the affected clients resolved the issue before AutoDiscover kicked in again, after som Google-ing I found that also the EXCH provider needs to be set to msstd:*.domain.com as Sferrero writes. This made AutoDiscover set msstd:*.domain.com.

Hope this is useful to some even though I'm not sure what our initial problem was and how it got fixed, the problem disappered before I set the EXCH provider


June 2nd, 2015 1:58am

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