Resolution
What Active Directory Connector Connection Agreements do I need for site-to-site migration from Exchange 5.5 to Exchange 2000 or later?
goal
Do I need AD Connection Agreements for site-to-site migration from Exchange 5.5 to Exchange 2000 or later?
fact
Exchange Migrator 2.2 SP1
fact
Exchange Migrator 2.3
fix
For site-to-site (Intra-Org) migration, the best practice is to use the Exchange Migrator EMCLI DIRSYNC to keep the Global Address List (GAL) synchronized. However, for Exchange 5.5 to Exchange 2000 or later Intra-Org migration, Exchange Migrator relies on ADC for mail flow and GAL synchronization. Therefore, you must create the necessary CAs.
For example, you have sites A, B, and C, where A and B are Exchange 5.5 (5.5) sites and site C is a mixed site with both an Exchange 5.5 (5.5) server and an Exchange 2000/2003 (E2K/E2K3) server. To migrate all the mailboxes into the E2K/E2K3 server in site C, you need to set up the following Active Directory Connector (ADC) Connection Agreements (CAs) need to be set up between the 5.5 Recipients Container and the AD Users' Organizational Units.
- A two-way CA, replicating objects between site C's 5.5 server and site C's Active Directory domain containing the E2K/E2K3 server
- A one-way CA, replicating objects from site A's 5.5 server to site C's Active Directory domain containing the E2K/E2K3 server
- A one-way CA, replicating objects from site A's 5.5 server to site C's Active Directory domain containing the E2K/E2K3 server
note
To prevent the creation of duplicate objects in the target, when you start to migrate a site, set the CA replication schedule to Never for the CA that is directly involved in the migration between the source and target. If you want to turn on ADC replication for the site after you have completed the migration, use a Post-Mailbox/Distribution List script to appropriately update the source mailbox and implement an ADC CA LDAP filter on the Connection Agreement so that the migrated objects are not duplicated nor reconnected by ADC.