Microsoft Defender email spoofing exceptions

[MrEprise]

I'm trying to get my head around adding a bunch of email addresses we use here for sending out things like Voicemail messages, Scans and notifications from PaperCut as well as emails from our Helpdesk software, but I can't get my head around the 'Spoofed senders' section in 'Tenant Allow/Block Lists' just to allow messages from these email addresses (basically [email protected], [email protected] & [email protected]).

 

We were using Barracuda for our email protection/security but for reasons outside my control, we've moved away from this and are now using Microsoft Defender for all of this... but I found Barracuda easier to figure out whereas Microsoft don't always make it easy to configure stuff like this and I'm stuck as all these emails keep ending up in quarantine flagged as "phish" and I've no idea how to set these as an exception.

 

Is there anyone who understands this better than me who can help?

[psydii]

Route the outbound messages through your 365 integrated mail infrastructure?  Papercut certainly integrates with it, as should any modern application. Configure an SMTP server over OAuth2 for Office 365 or Microsoft 365 | PaperCut 

 

We have some ancient ancient stuff lurking around, so we have an on-prem exchange server (mostly firewalled off from everything) through which the legacy apps can route traffic via on-prem authenticated accounts. We don't record the passwords, so there is no danger of account re-use. When a device is swapped out, or a new service created, we either create a new account, or if reusing the old one is appropriate, we reset the password - again not recording it in order to prevent a (lazy/overworked) admin from using it across multiple systems.

I should note that our Exchange server is not ancient and, with no end user mailboxes, is almost zero maintenance these days. By the time the OS on which it is installed goes EoL I expect the legacy apps that it exists to support will also have been replaced.