Send messages using additional Office 365 Exchange addresses

Last reviewed on August 8, 2014   —  No comments yet

I have an Office 365 account and have set up two domains @a.com and @b.com. My user's primary email address is alias@a.com however there are times I want to SEND FROM alias@b.com from Outlook desktop application. How can I do this?

When you have a secondary SMTP address assigned to an Exchange mailbox, you can receive mail sent to that address but all replies will be from your default SMTP address.

You have two options: Create a send-only POP account or an IMAP account to send mail from that address or remove the address from your mailbox and create a single-member distribution group (distribution list), mail contact, or shared mailbox for the address then give your mailbox Send as permissions.

Generally speaking, using a distribution group is the easiest solution to configure. Office 365 administrators can do everything in the online interface.

If you receive a lot of mail to the second address, a shared mailbox keeps the mail separate from the mail sent to your mailbox. Replies to messages in the shared mailbox will use the shared mailbox address but you’ll need to select the shared mailbox’s address to send new messages using it.

A distribution group will receive the messages and distribute the messages to your mailbox, instead of the messages being delivered directly to your mailbox. The only difference is that the To field will list the group name, not your mailbox name. For both new messages and replies you’ll need to select the group address as the From address. Mail contacts work much the same way, except transport (mail flow) rules are used to redirect mail sent to a mail contact.

To create a distribution group or mail contact and give a user send as permission, you need to follow these steps:

Remove second address from mailbox

For a Distribution Group:

  1. Create a distribution group and assign the address to the group
  2. Make your user account the only member of the distribution group and give it send as permission

To create a Mail Contact:

  1. Create the contact
  2. Create a rule to redirect the address to a mailbox
  3. Assign Send As permissions

When you want to send from the address, select the group or contact in the From field

 

Remove the address from mailbox

Log into the Exchange admin center and select recipients then mailboxes.

To remove second address from mailbox, select the mailbox name and click the Pencil icon (Edit), or double click on the mailbox name. Select email address from the list on the left, then select the email address you want to remove and click the minus icon. Click Save to save changes and close the dialog.

Remove the address from the mailbox

 

Using a distribution group

Step 1: Create the new distribution group

Next, you need to create a distribution group and assign the address to it. Still in the recipients section, select groups from the row above the mailboxes. Click on the plus sign and select Distribution group.

Add a new group

Create the new distribution group using the alias you removed earlier. Select the correct domain from the domain dropdown. Add group owners as members should be checked by default. If you are creating a group for other users, their name should be in the Owners list.

enter the display name and address

Wait a few minutes for the Active Directory to update and replicate then double click to open the newly-created group and continue with the next step.

 

Step 2: Assign Send As permissions

Your user account is the only member of the group and it needs Send As permission. You will probably want to allow outsiders to send to the group address.

To make these changes, click the Pencil icon to open the group for editing. If you want to allow anyone on the internet to send mail to this address, select delivery management and choose Senders inside and outside of my organization.

Select group delegation. Add your account (or the group owner’s account) under Send As. Click Save to save the changes and close the dialog.

edit the group

Using a Mail Contact

In older versions of exchange, many Exchange server administrators configured Mail Contacts and assigned Send As permission to other users in Active Directory Users and Computers and configured the contact to forward mail to a mailbox.

This is possible in Office 365 Exchange Online using the Add-RecipientPermission cmdlet and mail flow rules.

 

Step 1: Create the Contact

Log into the Exchange admin center and select recipients then contacts.
Create a new Mail Contact .

Create a new mail contact

If you prefer using PowerShell, the cmdlet is

New-MailContact -Name "displayname" -ExternalEmailAddress alias@domain.com -FirstName fname -LastName lname

 

Step 2: Create a Mail Flow Rule

Click the Mail flow link then the plus sign, selecting Create a new rule.

  1. Enter a name for the rule.
  2. Select Apply this rule if and choose the recipient is... .
  3. If you used a unique display name for your contact, select it and click Add. If you used the same display name as a mailbox, type the contact's email address in the check names field then click the check names button. Click OK.
  4. In Do the following, select Redirect to.
  5. Once again, if the display name is unique, select it and click Add, otherwise type the address in the check names field and click check names. Click OK.
  6. Click Save to save the rule and close the dialog. (More Options has additional options such as stop processing more rules.)

Create a rule to redirect email

Messages sent to the contact address are now being delivered to the user's mailbox. The mailbox user won't be able to reply using the contact address until they are given Send As permission.

If you prefer using PowerShell, the cmdlet is

New-TransportRule -Name "rule name" -SentTo email@address.com -RedirectMessageTo  mailbox@address.com -Mode Enforce 

More information on transport rules and conditions is available at Transport Rules

 

Step 3: Assign Send As Permission

You need to use PowerShell to assign send as permission to a contact. Log into Exchange using PowerShell and run the Add-RecipientPermission cmdlet, giving the mailbox user Send As permission on the contact. You can use the display name, alias, or email address in the contact and trustee fields. If the display names are not unique, use the email address.

Add-RecipientPermission "contact alias" -AccessRights SendAs -Trustee "mailbox alias"

To hide the contact in the address list so other users don't select it by mistake, use

Set-MailContact alias@domain.com -HiddenFromAddressListsEnabled $true

You can send as the contact by typing the email address (or display name, if unique) in the From field.

 

Using the address to send email

When you want to send from the address, select the distribution group name or contact in the From field. The first time you use it, you’ll need to select From > Another Email address and select your group or contact name. It can take up to 24 hours for the Offline address book to update, but it will be listed under All Groups or All Contacts immediately.

Select the group when sending mail

After the first use, the address will be listed under the From menu.

after the first use, it's listed on the From menu

Tools

RightFrom for Outlook

COM add-in for Outlook 2003/2007 that automatically fills in the correct From address when the user is responding to a message in another user's Exchange mailbox. (Use it with the UniSent add-in from the same site. UniSent keeps the outgoing messages in the Sent Items folder of the other users mailbox.) Version 1.7.0.4

SentRoute

Free Outlook 2000 COM add-in to file each sent message in a folder corresponding to the sending account in Internet Mail Only mode. Separate commercial version for Outlook 2000 Corporate/Workgroup mode and Outlook 2002 also available.

UniSent Add-in for Outlook

Outlook COM add-in for Exchange Server users who need to send mail from a second mailbox. The add-in ensures that messages sent with the second mailbox's From address or deleted from the second mailbox stay in the Sent Items or Deleted Items folder of the second mailbox. Version 7.4.0.1

More Information

You can create single member distribution groups in any version of Exchange server, however the screenshots and exact steps will vary in each version.

Written by

Diane Poremsky
A Microsoft Outlook Most Valuable Professional (MVP) since 1999, Diane is the author of several books, including Outlook 2013 Absolute Beginners Book. She also created video training CDs and online training classes for Microsoft Outlook. You can find her helping people online in Outlook Forums as well as in the Microsoft Answers and TechNet forums.

Please post long or more complicated questions at Outlookforums.

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