How to set the postmaster address in Office 365

By default when Exchange Online in Office 365 is setup for your organization, the postmaster address, e.g. postmaster@domain.com is set to postmaster@domain.onmicrosoft.com.

This means that when someone sends mail to your organization and gets an NDR back, the sender is: postmaster@domain.onmicrosoft.com.

If you want to change this, you can do so using PowerShell for Exchange Online.

The procedure for changing this is:

1. Connect to your Exchange online using PowerShell

2. Change addres using command:

Set-TransportConfig –ExternalPostmasterAddress postmaster@domain.com

 

This works for All P and E plans – I have not tested it yet for K plan.

This postmaster address is a tenant/organization level setting which applies to all domains in your tenant. It is not available to set the postmaster address on a domain level.