Hello Alex,
In my understanding, AD and DNS typically do not require User CAL, as they are the core functionality of windows server. CALs are required when accessing shared files on a Windows Server. This is because file access is seen as an additional service beyond the basic server infrastructure.
When users are only authenticating to the server for basic login and directory services and not accessing other services or resources hosted on the server, then they may not require User CALs.
I understand that Microsoft licensing can be confusing, it's important to note that licensing terms and requirements may change, and they can vary based on the specific edition of Windows Server and licensing agreements in place.
For the most up-to-date and precise information, it's advisable to consult the latest Microsoft licensing documentation or seek guidance from a Microsoft licensing expert who can provide information specific to your organization's needs.
LicensingguideWindowsServer2022Oct2022.pdf
Licensing Documents (microsoft.com)
Regards,
Karlie