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. is set to

This means that when someone sends mail to your organization and gets an NDR back, the sender is:

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


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.