Tag Archives: Exchange 2019

Check Server Core for Exchange 2019 Security Updates

When you want to check which updates are installed on an Exchange server you can navigate to Control Panel | Programs | View Installed Updates and you will see a list of installed updates, including the Exchange Security Updates.

When running Exchange 2019 on Windows 2019 Server Core there is no Control Panel and you can view the registry to check which updates are installed. Use the following command to view all installed Updates:

Get-ItemProperty HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*| select-object displayname

Or more specifically for Exchange Server:

Get-ItemProperty HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*| ?{$_.DisplayName -like "*Exchange Server*"} | Select DisplayName

This will show all software and updates for Exchange as shown in the following screenshot:

Get-DatabaseAvailabilityGroupNetwork Misconfigured

When installing a Database Availability Group in Exchange 2019 running on Windows 2019 Server Core, I got IP address configuration errors when creating the DAG. It did succeed, but when running the Get-DatabaseAvailabilityGroupNetwork command in EMS is get a ‘Misconfigured’ warning:

Or in plain text:

Identity ReplicationEnabled Subnets
-------- ------------------ -------
DAG01\MapiDagNetwork True {{,Misconfigured}, {,Misconfigured}}

This will be a DAG with two networks. One Mapi network ( for clients, and one replication network (

The requirements for an additional replication network in a DAG are:

  • No default gateway configured
  • No DNS servers configured
  • IP address must not be registered in DNS

When using Windows 2019 Server Core, the first two can be configured using the SCONFIG utility, but the last one is not that simple (but in Windows 2019 Desktop Experience it is just a matter of deselection the “Register this connection’s address in DNS” option when configuring the network interface).

When using Windows Server Core, you can use the Set-DnsClient command to configure this setting, combined with the Get-NetAdapter command.

Execute the Get-NetAdapter command to retrieve the network interfaces. In the following screenshot “Ethernet” is the regular Mapi network interface, “Ethernet 2” is the replication network interface.

To configure the DNS registration option, execute the following command:

Get-NetAdapter -Name "Ethernet 2" | Set-DnsClient -RegisterThisConnectionsAddress $False

When you run the Get-DatabaseAvailabilityGroupNetwork command again, both DAG networks will show up correctly.

Microsoft Teams and Exchange 2016 connectivity

More than a year ago I wrote a blogpost regarding Teams calendaring and Exchange 2016 integration: https://jaapwesselius.com/2020/04/07/microsoft-teams-and-exchange-2016/.

Currently I am working with a customer on this specific scenario, and to my surprise I ran into this Teams/Exchange connectivity test on the Microsoft Remote Connectivity Analyzer (https://aka.ms/exRCA). Open the Remote Connectivity Analyzer, select Microsoft Teams and click the Teams Calendar Tab button. Login with the account you want to test (in this example I have an on-premises mailbox on Exchange 2019, but works for Exchange 2016 as well) and click Perform Test.

Within seconds you will see if connectivity from Microsoft Teams to your Exchange server is working properly. Very nice!

Office Online server – Sorry there was a problem and we can’t open this document

For a current project I am working with Exchange 2019 and for OWA we want to implement Office Online Server. I did this in the past and blogged about it (Install Office Online Server 2016) so I thought it should not be a big deal.

Installed Windows 2016, installed prerequisite software, configured an SSL certificate, installed Office Online Server and created a new Office Web Apps farm.

After testing the https://fqdn/hosting/discovery and configured the organization configuration everything must be good.

When opening an attachment in OWA I do see the OOS environment, it tries to open a document and then generates this error:

“Sorry, there was a problem and we can’t open this document. If this happens again, try opening the document in Microsoft Word.”

When opening an Excel attachment, I get the following error message:
“Unable to open the file. We couldn’t find the file you wanted. It’s possible the file was renamed, moved or deleted.”

I know Office Online Server is sensitive for SSL certificates, but this was a regular Digicert certificate. Name resolution was fine as well. But the check https://fqdn/op/generate.aspx failed as well with the following (pretty useless) error:

“Server Error. We’re sorry. An error has occurred. We’ve logged the error for the server administrator.”

Unfortunately, nothing useful in the eventlog, or in the ULS logging on the Office Web Apps server. Asked colleagues, but they had only experience with Exchange 2016 and OOS.

After two days of searching, fiddling with the server, checking .NET versions (Windows 2016 comes with a newer version of .NET then required by Office Online Server), rebuilding the Office Online Server several times I realized it might be a TLS 1.2 issue. Exchange 2019 is using TLS 1.2 only by default, whereas Exchange 2016 can use multiple versions of TLS.

So, on the Windows 2016 server with OOS, I enabled strong cryptography in .NET and disabled older versions of TLS on Windows to fix the issue.

To enable strong cryptography in the .NET Framework, add the following registry key:


To disabled older versions or TLS, add the following registry keys:


[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\PCT 1.0]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\PCT 1.0\Server]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Server]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server]

After rebooting the Office Online Server, it worked as expected.

Security Updates Exchange Server December 2020

On December 8, 2020 Microsoft released a number of security updates for Exchange server. Despite the fact that Exchange 2010 is out of support at all, an important security update for Exchange 2010 was released as well.

Exchange versionKB ArticleDownload
Exchange 2010 SP3 RU31KB4593467Download
Exchange 2013 CU23KB4593466Download
Exchange 2016 CU17KB4593465Download
Exchange 2016 CU18KB4593465Download
Exchange 2019 CU6KB4593465Download
Exchange 2019 CU7KB4593465Download


  • The security updates are specific for each Cumulative Updates.
  • The upcoming CU’s for Exchange 2016 and Exchange 2019 will contain this security fix.
  • Install the security updates from an elevated command prompt.