topic Re: Microsoft 365 Notifications to Gmail in Peer-Peer Topics

Microsoft 365 Notifications to Gmail

brodgers — Tue, 30 Jan 2024 20:22:55 GMT

Good afternoon!

Does anyone have their Microsoft 365 configured to send notices, such as file-sharing notices, to an internal user's Gmail mailbox rather than their Exchange mailbox? In Exchange Admin, I have a connector configured for aspmx.l.google.com and a transport rule to route all messages for our email domain through the connector.

Things are working fine on the Microsoft 365 side. It is sending notices to Gmail as expected. My problem is on the Gmail side. It appears that Gmail is performing SPF checks on the internal M365 servers rather than the SMTP gateway that transfers the message to Gmail. This is causing the messages to fail SPF and are being sent to spam.

I have include:spf.protection.outlook.com included in our SPF record and have DKIM configured for M365 with the appropriate DNS records. Why is Gmail testing SPF on internal servers rather than just the SMTP gateway it receives the message from? Is there any way around this behavior?

Thanks!

Brad

Re: Microsoft 365 Notifications to Gmail

icrew — Tue, 30 Jan 2024 20:39:08 GMT

I don’t have direct knowledge of this specific situation, but perhaps https://support.google.com/a/answer/60730?hl=en has something to do with it?

Re: Microsoft 365 Notifications to Gmail

brodgers — Tue, 30 Jan 2024 21:42:00 GMT

@icrew thank you for pointing me in the right direction. The problem was self-inflicted. For whatever reason I added the MS365 endpoint IPs as inbound gateways.

Re: Microsoft 365 Notifications to Gmail

Kim_Nilsson — Wed, 31 Jan 2024 07:06:35 GMT

Yes, I'm fairly sure that Inbound Gateway should only be used when the MX record points to M365 for the domain address used in Workspace.