It's not unusual for an Exchange server mailbox to have several SMTP addresses associated with it - often for sales and support, or the Exchange server is running 2 domains (domain1.com and domain2.com) with each user having address from both domains assigned to their mailbox. The mailbox users want to be able to send messages from any of the associated SMTP addresses, and this is not possible with Exchange server. When you send using Exchange, it always uses the default SMTP address. Creating a separate mailbox for each address adds its own problems as managing multiple mailboxes can be a hassle, but its often the best option, especially if you use Outlook 2010.
There are several ways to handle this problem:
- Create IMAP accounts in Outlook, one for each address. The user chooses the account they want to use when they compose the message. You can also create a send-only POP account.
- Create distribution groups on the server for the secondary addresses and make the mailbox the only member. (Remove the secondary addresses from the mailbox before setting up the groups.) Give Send as permission to each distribution group.
- Install a utility that will allow you to choose the From address
- Split the addresses into multiple mailboxes and use Outlook 2010 and up, which supports multiple Exchange accounts in the profile. You can use shared mailboxes instead (does not require an Office 365 license) but you will need to select the shared mailbox address when you send new messages.
None of the methods are perfect, although Outlook 2010 (and up) handles it the best, by allowing two Exchange accounts in the profile. It will automatically choose the sending account based on the folders you are viewing when you begin a new message.
Using a Distribution Group
Next to separate mailboxes, using a distribution group (DG) may be the second best option. With the second SMTP address set up as a distribution group address and the primary address as the only member, mail to the DG is delivered to the users mailbox. The administrator needs to give the user's primary account Send as permission to the address of the distribution group. When messages are received by the distribution group, they are delivered the users mailbox, just as they are now. When the user replies, he can select the DG as the From address. It's not perfect and the user needs to remember to set the From address, but it works. You can do something similar with email enabled public folders or AD contacts, but a DG will deliver messages sent to the address to your mailbox.
Step by step instructions for Office 365 Exchange Online are at Send messages from additional Office 365 Exchange addresses
Office 365 mailbox may have multiple SMTP addresses and receive mail sent to any of the secondary addresses but Exchange Online always uses the primary SMTP address for sending messages. ChooseFrom 365 application allows Office 365 users to send a message with any of their own SMTP addresses as the From address. New feature: multiple display names associated with a single SMTP address. The application is a cloud service.
Exchange server mailboxes can have multiple SMTP addresses and receive mail sent to any of these addresses but Exchange will always use the primary SMTP address for sending messages. ChooseFrom allows users to send a message with any of their SMTP addresses as the From address.
Lucatec Mask Add-in for Outlook is used with Exchange server accounts, allowing replies from a shared mailbox or public folder, automatically entering the folder or mailbox's email address in the From field. Lucatec Mask will automatically determine the correct sender address to use based on the mailbox or public folder the user is currently using in Outlook. It also offers the option to move or copy the sent message to the relevant account's Sent Items folder (or Public Folder). It supports shared Exchange Server accounts and Public Folders with email addresses. Works with Outlook 2000-2010. Version 3
Proxy Manager lets you send emails from Outlook using any alias (proxy) SMTP address with an arbitrary display name from your Exchange account, hosted or on-premises. There are no server components, everything is done on the client side - just install Proxy Manager, and you are ready to go! Select one of your proxy addresses and click Send. Outlook 2010, 2013, 2016 and 2019 are supported.
COM add-in for Outlook 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.)
SelectSender is a tool for Office 365 users who need to send mail from different addresses. This utility allows an Office 365 OWA user the ability to easily select the From address of the new, replied or forwarded message. SelectSender can be used only in cooperation with ChooseFrom 365 cloud service.
Outlook COM add-in that lets you automatically insert in the "From:" or "Have replies sent to:" field any address/alias that you need for each outgoing message. If you're mainly concerned with getting From right when replying to mail from another user's Exchange mailbox, RightFrom, from the same author, would be more appropriate.
ShowAlias allows an Outlook 365 user to see if an e-mail has been sent to the main (default) e-mail address or an alias address. This is an Office 365 addin and works with Office 365 and Outlook.com mailboxes in Outlook desktop and Outlook on the web.
SmartReply is an utility for Exchange Server users who need to send email using different addresses. This utility provides an Outlook user with the ability to easily select the From address of the new, replied or forwarded message. The message can be replied with the same From address as original message has been sent to. Also you can set a different signature for each e-mail address. Supports Office 365 Exchange Online.
SmartReply 365 is an utility for Outlook desktop (Windows) users who have enabled the Microsoft feature to send emails from an alias in Office 365. This utility will automatically populate the proper From: address when you reply to or forward a message received as alias. In other words, if you get a message addressed to email@example.com and hit Reply(Reply All, Forward) button, the replied/forwarded message will have firstname.lastname@example.org in the From: field. The utility is an Outlook COM add-in.