Email to Office365 from Internal devices 2025

2nd January 2025

Microsoft is making changes and not keeping their documentation up to date

Requirements:

DNS/SPF record must include the PUBLIC IP address or DNS name where the email will be coming from. You can check using https://www.whatsmyip.org/ and comparing to https://mxtoolbox.com/spf.aspx

Create a CONNECTOR in Office365. Exchange Admin center, Mail Flow, Connectors, Add a connector, Your organizations email server, Next, Add a Descriptive Name, Check Turn It ON, Next, By verifying that the IP ADDRESS…, enter your PUBLIC IP from the previous step, Click +, Next, Create Connector

Newer printers and devices support authenticated and encrypted emails but older devices do not. In this case you will need some software to relay emails. Cheapest+easiest method I have found is to use NextCloud, which is a complete OS+Software combined, so no Windows license, no software license. If you are worried about reliability, make 2, it’s the same price. Has a web GUI to keep it simple.

NextCloud

Administration setting, Basic settings, Email server

Send mode: SMTP
Encryption: None/StartTLS
From Address: must be a valid address, I used a group name as that doesn’t cost extra
Server Address: use the format yourdomain-ext.mail.protection.outlook.com
Authentication Required: Yes
Credentials: use the from address, if different the Credentials account will need send-as permission to the From account, and that is extra work.

Click test and NextCloud will send an email to the From address