Active Administrator Multi-Forest Support (4376375)

Active Administrator Multi-Forest Support

It's possible to manage several forests from a single Active Administrator instance ?

Managing several forest from a single Active Administrator instance is not an officially supported scenario.
Best practice is to deploy a dedicated Active Administrator instance per forest.

Even if it's not recommended/supported, a single Active Administrator instance can manage several forests... but it could have limited functionality in some scenarios depending on the environment. 

In order for this single AA instance to work with the other forests, the following items are needed. 

- Required ports open between the AA instance and the target forest. 
KB Article: What are the Port Requirements for Active Administrator?

- Forest two-way trust between the AA instance and the target forest.

- Add the AA service account to the Built-In Administrator group on the target forest.

- DNS/Conditional forwarders between the AA server, SQL server with the AA database and target forest.

- The account used to deploy the agents on the target forest need to have access to the AA SQL database.

With these required items, it's known that an AA instance can manage several forests. 
However thoroughly testing has not been done and certain features could experience errors/issues.