Don’t Get Blocked! M365 & ExchangeDefender: How to Ensure Smooth Outbound Email Delivery

M365 and ExchangeDefender Outbound Limitations

As the Microsoft M365 network grows, the email abuse originating from it is also on the rise. One area that clients often get compromised first is the use of their tenant to relay unauthorized mail and spoofed or null/system messages. ExchangeDefender protects clients from this activity and our security policy blocks the relay of external domains and null senders.

We understand that some clients may want to take the risks or want to send out-of-office (OOF) messages no matter what (even if it fails/errors out). This can be done entirely within Microsoft M365 and we’ve written a step-by-step guide that will take you approximately a minute to complete at https://admin.exchange.microsoft.com

Once you’ve created a new connector and enabled a new mail forwarding rule you’ll have to include: spf.protection.outlook.com to your SPF record and publish the new DKIM key. Check that everything is published right and enabled and that’s it.

As we’ve discussed in the past, unauthenticated and unauthorized (faked or forged or unsigned) mail is on the way out and the email security landscape has only gotten worse since we published that in 2022. If your email system has unique routing and delivery needs, ExchangeDefender can build a custom solution for you. We’ve helped organizations modernize and support legacy email methods for years and we’re sure we can help you as well.