Under what conditions is it necessary to actively configure a trust relationship?

Actively configuring a trust relationship is particularly necessary when integrating with another operating system because different systems may have varying authentication protocols and security models. In scenarios where an organization operates multiple operating systems (such as a Windows environment trying to interact with a Unix-based system), a trust relationship allows these systems to exchange authentication and authorization information securely.

This configuration ensures that users from one system can access resources on another system without having to create separate accounts or deal with compatibility issues. It helps maintain security while providing seamless access, making it essential during such integrations.

In other contexts, like having just one forest or migrating to a new server, trust relationships are less critical because there is usually a single identity management system in place. Hybrid cloud solutions might also require appropriate configurations, but the trust relationships are often managed differently, relying on cloud service offerings that abstract some of the traditional trust requirements.