365 Shared Mailbox - no storage

Question

Hello,
I am setting up automated email functionality for an application. We are on 365.

I need to setup a mailbox so that the server / software can authentication with 365 when sending the email. However, I don't want it to save anything. I don't want the sent messages to accumulate in the shared mailbox's. Sent Items or anywhere else. This is because there could be some confidential information, and I think it is best to not save it anywhere unnecessarily.

How do I do that? How do I setup a mailbox that can authenticate and send mail, but not actually store the mail that it sends?

I looked in the transport rules, but didn't see any options that looked like what I wanted. I also looked at the Retention policy. It looks like there is a 1 day policy for sent items. I could use that, but I was hoping to not store at all.

Thanks,

Answer 1

Hi, @NW Admin

You may also have the application authenticated with Office 365 and use SMTP AUTH client submission to send emails.
The detailed steps are introduced in this document: How to set up a multifunction device or application to send email using Microsoft 365 or Office 365
Please refer to the Option 1 part.

While, by default it will leave a copy of the message in the "sent items" folder.
You may need to run this command to change the setting of the mailbox via Powershell:

Set-Mailbox -Identity <the specific mailbox> -MessageCopyForSMTPClientSubmissionEnabled $false  

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Answer 2

Why do you need to authenticate to 365? Just send the email anonymously from the application as that mailbox. The messages wont exist anywhere except in the recipients mailbox ( wherever you are sending the, to) and within the application itself.

Answer 3

Thanks to both of you for your help. The -MessageCopyForSMTPClientSubmissionEnabled seems to have provided the intended functionality.