Forward emails to external address in Exchange Online

There are cases we have to forward a mailbox to an external address, e.g., gmail.com, yahoo.com, or other address that does not belong to your domain. For example, if you just want to forward all emails of an employee to an external address, you can use the "Mail Flow" feature in Exchange server. Let's see how it can be done.

Step1  Create Mail Contact

Open Exchange Admin Center and create a Mail Contact



Step2. Configure Forwarding

Open Exchange Admin Center and select the mailbox you need to forward the email to an external address. Open properties of the mailbox.


Go to mailbox features and scroll down and click on View details under Mail Flow 


Tick Enable forwarding and click on Browse


Select the newly created mail contact and click OK


If you want to deliver emails to the mailbox as well please tick Deliver message to both forwarding address and mailbox. I.e., Email will be delivered to the mailbox, and one copy will be forwarded to the external address if you enable this.

Click OK


Click Save


Email forwarding to external domains is blocked by default by Antispam. We have to create an Outbound policy to allow that particular mailbox to forward to external addresses.

Open https://protection.office.com/antispam  and click on Create an outbound policy. Source here.


Automatic forwarding should be enabled and specify the sender. I.e., the mailbox which forwards emails to an external address. Click Save


Mailbox forwarding to an external email address has now been set in Office365.

I have written articles to cover the Exchange administration on all versions of Exchange (see below):

• Easy CSR creation in Exchange2007 and higher versions.
• Count Mailboxes in your organization in Exchange2007 and higher versions.
• Block OutlookAnywhere Access to some users in Exchange2010 and above versions.
• To clear certificate error and set URLs in Exchange2007.
• To clear certificate error and set URLs in Exchange2010.
• To clear certificate error and set URLs in Exchange2013.
• To clear certificate error and set URLs in Exchange2016/2019.