Overview of delegation in an Office 365 hybrid environment

Van toepassing: Exchange Online


Microsoft Exchange Online customers have problems in the functionality of their Full Access, Send As, Send on Behalf of, and Folder permissions.


For Office 365 hybrid delegation to work as expected, multiple requirements must be met.


Office 365 hybrid delegation requires a specific configuration in the cloud and in the on-premises Active Directory Domain Services (AD DS) environment. The following list discusses the different permissions and how they work in a hybrid deployment.

    Full Access

    Send As

    • Send as works in many scenarios, but is not fully supported by Microsoft as outlined in Permissions in Exchange hybrid deployments
    • Send As permissions enable mail to be sent from another mailbox that enabled the mail user object’s primary email address.
    • Permissions are granted by administrators by using the Exchange Admin Center or Remote PowerShell (Add-ADPermission in on-premises Active Directory and Add-RecipientPermission in Exchange Online).
    • Permissions must exist in the sending user’s forest. For example, if a user’s mailbox is moved to Exchange Online, the Send As permissions must be listed on the mail user object that represents the on-premises mailbox.
    • Permissions are not synchronized by Azure AD Connect.
    • Permissions set in on-premises AD DS must be manually added in the Exchange Online for full functionality. For more information, see Exchange hybrid deployment considerations.

    Folder access

    Send on Behalf of

    • "Send on Behalf of" permissions enable mail to be sent on behalf of another email address
    • Permissions can be granted by users by using Outlook or by administrators by using Exchange Admin Center or Remote PowerShell (Set-Mailbox cmdlet).
    • Permissions must exist in the sending user’s forest.
    • By default, the PublicDelegates attribute (also known as the GrantSendOnBehalfTo attribute in Exchange on-premises) is synchronized to Exchange Online by Azure AD Connect.
    • Additional configuration is required to synchronize the PublicDelegates attribute with on-premises AD DS. This configuration requires enabling Exchange hybrid deployment settings in Azure AD Connect. For more information, see Exchange hybrid writeback

      Optional features
    • If Exchange hybrid deployment setting is not enabled, the "Send on Behalf of" permission has to be added manually by an administrator by using Remote PowerShell. To do this, refer to Delegate can't send "on behalf of" after migration to Office 365 hybrid environment.


    Note Be aware that delegation also affects external calendar sharing. For more information, see Unable to accept an external sharing invitation by using Outlook in a hybrid environment.