Exchange 2010 - sending/receiving from more than one domain

I have an exchange server, which currently uses as the domain name for all of the emails.

We've recently gotten a new domain name A few of the employees need to send and receive email from as well as from, via Outlook and via OWA.

I've setup the MX records, added to the accepted domains, and gone into the appropriate recipient users and setup an "email address" for them something like "".

Receiving emails works fine to their mailbox.

Now the users need to be able to SEND email and have the from address say "", and I'm having trouble with that.

In OWA, you can select the "From" address, but only the one email address shows up. I need this to also show

How do I do this?
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Marc DekeyserSr Premier Field EngineerCommented:
For this to work you need to create a second mailbox with the proper mail address on it and grant the proper user send rights on that mailbox. You cannot send from the SMTP addresses associated with the account, except for the primary account.

So for user Alpha with email address you added the address Only his primary email address is still so he can only send mails with the From field showing up as

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Alan HardistyCo-OwnerCommented:
The alternative to the above solution (which is usually the preferred solution) is to setup a POP3 / SMTP account alongside the Exchange account, disable the POP collection leaving just the ability to send out which is detailed in the following link:
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Marc DekeyserSr Premier Field EngineerCommented:
Yes you can indeed do that. And if you do not have permissions to send on behalf of that non existant email address you will get an NDR. If you do manage to get it out somehow you could very well be caught up in anti spam filters due to alternate heading stamps...
Frosty555Author Commented:
Geminon - I hesitated when creating a "New User Mailbox" because I needed to associate it with an account in Active Directory. I couldn't associate it with my existing account since it already had a mailbox. So I need to create a whole new user in active directory as well?


MYCOMPANY.local\jsmith      -->
MYCOMPANY.local\jsmith2    -->


If this is the case, I have a few questions:

1. How do I set up the default email address policy (or create extra email address policies) in Exchange so that certain users have the, and certain users have

2. When I create the new user, do they belong to the same MYCOMPANY.local domain? If so... how do I keep these users as "exchange" users only, and not let them, for example, login to a computers on the domain? I want to not confuse my users with a second user account if at all possible.

3. I'll try this again... but the last time I tried to "Manage Send As permissions" from EMC for the user I got an "Access Denied" error from the Exchange Management Console. Any idea why that could be? I'll get the exact error message for you.

4. Lastly - does Outlook have an easy way to show both user mailboxes on the left side column at the same time? Or does the user have to "flip flop" between the two? What about in OWA?
Marc DekeyserSr Premier Field EngineerCommented:
There is no way to associate 2 mailboxes with one user, ergo you need a new user as well :).

Send as permissions:

Your address policy depends on how many users you have and what you have set up now. I would, personally, do it manually if there is a small number of users involved. If you have a large number of users needing this you can work with custom attributes to set the value. (LDAP filters):

Depending on how your address policies are configured now you would need to rethink them.
Frosty555Author Commented:
Hi Geminon,

Okay, I did that and I figured out the Send As Permission and Full Access Permission issues I was having earlier. And you're right its easier to just turn off the email address policies for those few users that need special setup.

In OWA I can easily open the second mailbox, so that works fine.

Outlook is being more troublesome. I go into Exchange Account settings->Advanced->Additional Mailboxes, and I have picked the second "user" mailbox so it shows in the left hand side pane along with my normal mailbox.

All looks good, except that I still don't see an easy way to actually pick which email address my users are sending FROM. There's no obvious way to do it in Outlook 2003 that I can see...? Is there something I'm missing?
Alan HardistyCo-OwnerCommented:
Marc DekeyserSr Premier Field EngineerCommented:

You should be able to change that via the FROM field now.
Another option instead of creating another mailbox is creating new distribution group with second smtp address, which delivers mails to user mailbox. That user also have send-as permissions on that distribution group. In that case you don't need second mailbox. It can get costly if you have per-mailbox exchange antivirus.
Here you have also 3rd party tool - choosefrom:
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