Hi everyone,

Hoping someone can help with my basic understanding of FIM Galsync.

The background is that we currently use FIM 2010 R2 Galsync along with  FIM 2010 R2 + WAAD connector to produce a consolitdated Office 365 GAL, referencing several Active Directory forests. This solution was implemented almost 3 years ago by an external consultant.

As each new Active Directory forest comes onboard, we deploy an on-premises Exchange 2013 Management server (or utilize an existing one if the forest has Exchange deployed) and add a new MAs to the Galsync and Dirsync servers.

To date as we create the new Galsync MAs we create and specify a Galsync target container, and this results in over 120K contact objects being provisioned in the new forest.

I'm wondering whether we actually need this Galsync target container in all the connected Active Directory forests, given that the synchronization to Office 365 is only done from the Galsync target container within the forest where FIM Dirsync server is installed.

I understand the need for the Galsync target container if all the Active Directory forest had on-prem email implementations, as Galsync would then maintain "repliability" if users moved between forests. However in this case where Galsync is deployed purely for Office 365 purposes I can't see the need.

My research found a document "Microsoft Identity Integration Server 2003 - Global Address List (GAL) Synchronization" which despite its age has a great technical description of Galsync. It mentions that provisioning of contacts can be disabled by the simple expedient of not defining a Galsync target container within the Active Directory forest in question.

Can anyone advise whether I can indeed disable provisioning of Galsync contacts within downstream Active Directory forests in this particular scenario? To be honest the Galsync contacts seem superfluous except in the forest where the FIM Dirsync server is homed.