When you migrate a large number of mailboxes, you need to provide credentials for the mailboxes on the migration Source in order to gain access to the mailbox. You can do this by obtaining the logon credentials from each user, but this is a burdensome and error-prone approach. Much better is to use a single set of administrative logon credentials, then apply the administrator credentials to all of the mailboxes targeted for migration. There are two approaches to doing this: impersonation and delegation.
Impersonation works by allowing the migration administrative account to impersonate a series of user accounts. Delegation, on the other hand, is the process of a computer user handing over their authentication credentials to another user, in our case, to a migration administrative account.
The links below offer more instructions and information on impersonation and delegation.
This article covers the following:
- What does delegation and impersonation mean in reference to migrations?
- Which approach is best suited to various migration scenarios?
- How are impersonation and delegation enabled and configured?
A comprehensive set of instructions for migrating from Exchange or Office 365 environments according to the software version you are using.
When using MigrationWiz and Exchange Web Services (EWS) to migrate to or from Exchange Online, you should use impersonation (not delegation) when accessing user mailboxes. Using impersonation not only solves some potential throttling issues, but more importantly, allows you to scope the impersonation to a specific set of user mailboxes.
The objective is to limit the scope of mailboxes that are migrated using the impersonation rights. You accomplish this by implementing an impersonation scope filter. This is a common requirement in migrations where only a subset of an organization's mailboxes are scheduled for migration, for example, in migrations related to mergers and acquisitions.
Click through and refer to the section that applies to the appropriate Destination. This article refers to the use of delegation to log in to individual user mailboxes using an "admin" account that has full access rights to each mailbox.
Note: We strongly recommend using impersonation, rather than just delegation, when migrating to Office 365. However, when migrating to Exchange, rather than Office 365, either delegation or impersonation can be used. Refer to KB005004 for more information on this decision, and the exact steps to set these up.