Does PCNS Require Forest Trusts?
PCNS connects to MIIS over an RPC channel using Kerberos authentication. It explicitly requires mutual authentication, meaning PCNS must trust where it send the password, and MIIS must trust that is is receiving the passwords only from a DC. If PCNS and MIIS live in the same forest, the trust is implicit. If PCNS lives in a separate forest from MIIS, then a forest trust must be established before passwords will flow. If PCNS and MIIS are in Froest A, and you want to syncrhonize the passwords to Forest B, then no explicit trusts need to be defined. MIIS uses the credentials on the MA to connect and set the password. On the other hand, if PCNS is in Forest A, and MIIS is in Forest B, and you want to synchronize passwords from Forest A to other CDs, then a forest trust is required before PCNS wil flow passwords into MIIS. Again, once the passwords are in MIIS, MIIS uses the credentials on each MA to connect and set the password.