Forum Discussion
SMTP Relay configuration in full hybrid environment
Hello, I have a question regarding the configuration of the SMTP Relay in Full Hybrid environment. My infrastructure is full hybrid with a 2016 exchange server on premise. We also utilize a Barrauda Cloud gateway so all incoming mail flows to the Barracuda, then to the on-prem 2016 Exchange server and then from the 2016 Exchange to Exchange online.
Most of my mailboxes (and soon to be all) have been migrated to Exchange online. SMTP relay is currently being provided on the on-prem server for internal and external email, but we want to minimize the footprint of the on-prem server to a management platform only for security conserns and use M365 smtp relay.
Currently my public dns record for autodiscovery points to the exchange onprem server (Alias CNAME is exchange.domainname). MX records must point to the Barracuda network.
When trying to folllow setup for M365 SMTP relay the M365 admin center is questioning my MX and CNAME records beacuse they are not what it expects.
I don't use public folders. Is smtp relay to the online Exchange server possible in my environment? How do I configure this?
- Hello
Where exactly are you receiving this complaint? while creating the connector?
Confirm please you are using Option 3 here https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365- Yes when creating/viewing the connector in the Admin Center it is complaining about the DNS record. It always expects to see yourdomain-com.mail.protection.outlook.com but our MX records contain the smarthost data instead. I expect M365 has no way to detect a defense gateway in front of thier services. Our autodiscover record is also not what is expected it is looking for autodiscover.outlook.com and we are still pointed at our domain.
- Can you describe what options did you choose to create the connector? or add a screenshot, hiding any private info.
