We have a Windows 2008 Enterprise R2 SP1 server with multiple accepted domains configured on our Exchange 2010 console.

Configuration of exchange 2010: In exchange console, under organization configuration > hub transport > accepted domains, we have:

domain1 > authoritative > default = true
domain2 > authoritative > default = false
domain3 > authoritative > default = false
domain4 > authoritative > default = false

We are able to RECEIVE e-mails on ALL the above domains.

Just to be clear: I can receive emails to userX@domain1.com , userX@domain2.com, userX@domain3.com and userX@domain4.com without any problems. I am able to send email from userX@domain1.com (the default domain). However, when trying to send emails from userX@domain2.com, userX@domain3.com, and userX@domain4.com, I receive the following error:

Delivery has failed to these recipients or groups:

destination_example_email You can't send a message on behalf of this user unless you have permission to do so. Please make sure you're sending on behalf of the correct sender, or request the necessary permission. If the problem continues, please contact your helpdesk.

If I change the primary email address for userX to userX@domain3.com , I am able to send as userX@domain3.com and only from that mail.

The question:

How can I enable sending emails from ALL the authoritative domains at any single moment without having to manually change the default email address of the user?

  • I would also like an answer to this topic.
    – gpresland
    Feb 6, 2012 at 21:58

4 Answers 4


We've found a work-around in the meanwhile.

If we split up the accounts into 4 different accounts, and grant the correct permissions, we are able to send as any user.

However this is a very pale solution. this would multiply the number of accounts in both AD and Exchange

Still searching for a official fix on this.


This answer assumes that you are attempting to use Outlook as your mail client.

This is a common problem that I have run into. The way to do it is to setup a dummy account in Outlook as a POP3 account and SMTP with the alias/alternate email. Then turn off the automatic checking of mail for the POP3 account by removing it from the default receive group. An authenticated SMTP session can send email as any alias that the user has. This also changes the "From" field in new emails to a drop down that can be changed.

This is a good article on setting this up: http://www.thirdtier.net/how-to-configure-outlook-so-you-can-send-from-an-alias/


In an Exchange environment an user can only send emails using a sender address he/she owns (unless delegation is used); if an user has a primary address user@domain1.com and secondary addresses user@domain2.com and user@domain3.com, all of them will work; of course, it's up to the user to select the right sender address in Outlok or OWA: if nothing is explicitly selected, the primary address will be used.

But if an user doesn't have an address assigned to him/her, Exchange will refuse to send a message using that sender address.

If you want all your users to have an email address in all your SMTP domains, you'll need to update your address policy to give each user an address in all domains; this will allow them to use any of their addresses as the sender address when sending a message. It doesn't matter if an address is primary or not: an user will be able to send messages using any address he/she owns.

  • I just noticed this is a 9-years-old question. However, the answer still applies. Use the address policies to give each user an address in all you SMTP domains, and they'll be able to use each address they own as the sender address.
    – Massimo
    Jan 24, 2021 at 3:23

As far as I am aware each mailbox can have only one primary email address, this is the reply address the recipient will receive, even if each mailbox has multiple alias email addresses.

I would create a mailbox for each domain. Then give the user full mailbox access to the domain2.com, domain3.com and domain4.com mailboxes, and add these as additional mailboxes in the Outlook profile.

When the user sends an email they will then be able to choose each the relevant email addresses from the from field.

To complement this I would set an autoforward from the additional domains to the domain.com mailbox so the user doesn't have to check each mailbox.

It's not a perfect solution but will do the job.

  • Instead of using users you can also use distribution groups. I don't remember how to configure this exactly, but I can send mail with one of my distribution group's addresses from outlook here Jun 6, 2017 at 17:04

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