When you click "Open Windows Security" on Windows Server 2019 you may receive an error "You'll need a new app to open this windowsdefender"...

When installing or uninstalling Exchange Cumulative Update (CU) installation may simply crash. If you find "Could not load file or assembly 'Microsoft.Exchange.CabUtility.dll' in ExchangeSetup.log”, make sure that you have correct Visual C++ Redistributable Package for Visual Studio installed on your Exchange server. Check Exchange installation prerequisites....

Windows clients and servers will use DHCP for IPv6 addresses even when you set static IPv6 address. Not only that, but Windows client will prefer DHCP IPv6 address over static one. On below picture we can see that ipconfig returns two IP addresses....

DKIM will be more and more important in the future for authenticating legitimate e-mails. For this reason, I like to enable DKIM for all my domains in Office 365 tenants where DKIM is really easy to enable....

There is always a big discussion how safe it is to synchronize "password" to Microsoft cloud – Azure AD. First of all, passwords are never synchronized to the cloud. Actually, the result of, 1000th iteration of the HMAS-SHA256 hashing function is being synchronized to the cloud. Microsoft is in this case also using per user salt when they are creating hash to be sent to the cloud. This means that even when two users are using same password, hash in the cloud would look different....

Microsoft MFA has become a popular way of protecting access to Office 365 and Azure services. For additional security the latest version of Microsoft Authenticator allows you to require verification every time you run the app on your iOS device....