Apple offers the ability to define multiple e-mail aliases to send from in their e-mail client, especially useful when you concentrate all your e-mail addresses into one account and you need to respond from a specific address. This is found both in the Mac version and in the iOS version of Mail, but only for IMAP accounts (might also work for iCloud or Gmail accounts). For Exchange accounts, the E-mail address field is read-only.
What I discovered is that you can get over this limitation and define aliases even for an Exchange account, thus eliminating the need to add more e-mail accounts that would complicate things and minimise battery life.
What you need to do is define an alternate SMTP server and set it as default, and then the E-mail address field gets editable and you can put your e-mail addresses separated by commas. After that, you can change back to the Exchange option for sending mail and the aliases remain valid for use. To be able to change them, you will have to choose the alternate SMTP server again.
Of course, in order to be able to really send from the defined e-mail addresses, the e-mail account has to have those e-mail defined on the Exchange Server or Exchange Online, but that’s easily achievable.
Applies to the Mavericks version of Mail for Mac.
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