Which DNS namespaces does Exchange 2019 support?

Exchange 2019 supports contiguous, noncontiguous, and single label domains within its DNS namespaces. Understanding what each type of domain means is crucial to grasping why this is the correct answer.

Contiguous domains are those where the child domain is directly hierarchically related to the parent domain (for example, if "child.example.com" is a child of "example.com"). Noncontiguous domains involve domains that are not directly connected in this way, where a domain can exist independently but still be part of the same forest (such as "example1.com" and "example2.com" existing in the same organization).

Single label domains are those that do not have a dot in their name, meaning they do not include a top-level domain—these are often simpler names used within local networks.

Exchange 2019's capability to work with all these types of DNS namespaces provides flexibility for organizations with varying domain structures. This ability is essential for seamless mail flow and ease of management across different domain configurations. By accommodating various domain structures, Exchange 2019 can cater to diverse enterprise environments, thus supporting organizations with different requirements and configurations.