506 votesAaron supported this idea ·Aaron commented
This is a very big issue for us as well. We have users (single mailbox/identity) within our enterprise who have roles with multiple organizations, with different organization-specific email addresses. They receive mail addressed to all of their proxy addresses, but are currently unable to send it "From" a specific email address, because Exchange rewrites the message with the primary SMTP address on the way out. The mail clients are capable of supporting multiple From addresses. Competing services are capable of supporting it. We just need Exchange to support it.
4 votesAaron commented
This appears to be a duplicate. Let's consolidate all of these votes under https://office365.uservoice.com/forums/273493-office-365-admin/suggestions/10588884-sendas-and-email-alias.