Bear in mind the advice on these things changes over time, and it's possible that the situation in the past may not have been as clear cut.
As an example, at one point in the past (I think in the 90's?), Microsoft recommended using .local for AD domains, whereas now they explicitly recommend against it.
As an example, at one point in the past (I think in the 90's?), Microsoft recommended using .local for AD domains, whereas now they explicitly recommend against it.