Create a Forwarder in Exchange
Enable communication between migrated and non-migrated users during coexistence.
Overview
During coexistence migration scenarios, you need to configure mail forwarders to enable communication between users who have been migrated to Office 365 and those still on Exchange on-premises.
Three-Step Process
- 1. Create a mail contact for the migrated user
- 2. Hide the contact from the address book
- 3. Configure mail forwarding to the contact
Forwarder Mail Flow
PowerShell Method
Use these PowerShell commands in the Exchange Management Shell to create a forwarder for a user named "Bob":
1 Create Mail Contact
New-MailContact -ExternalEmailAddress 'SMTP:bob@domain.onmicrosoft.com' -Name 'bob thecontact'
2 Hide from Address Book
Set-MailContact bobForward -HiddenFromAddressListsEnabled $true
3 Enable Forwarding
Set-Mailbox bob –ForwardingSmtpAddress bob@domain.onmicrosoft.com
Manual Method
Using Exchange Management Console
- 1 Navigate to Recipient Configuration
- 2 Select the user mailbox
- 3 Open User Properties
- 4 Go to the Mail Flow Settings tab
- 5 Click Delivery Options
- 6 Configure the target contact for forwarding
Important Warning
⚠️ Critical Configuration
Do NOT check "Deliver Message to Both Forwarding Address and Mailbox"
Enabling this option would create duplicate messages: the mail gets delivered to the Office 365 mailbox via forwarding, and then the same message is migrated again from the on-premises mailbox during delta pass migration.