Forum Discussion
DKIM/DMARC and onmicrosoft.com
Hello We have run into an issue with DKIM and DMARC. We have three domain names in use within our Microsoft 365 tenant. We use Proofpoint Essentials to filter inbound/outbound email to all of them....
Same here. I have searched all there is to be searched to no avail 😞 Our main problem is with D/L. DKIM alignment fails when a D/L member (with outside domain) sends out to D/L. Furthermore, while our customdomain.com passes all DKIM/Dmarc, when we check for customdomain.onmicrosoft.com, DKIM fails for all existing selectors. smh.
- Well, I assume that it does not matter so much. Email from our tenant originates from Microsoft's mail servers which are Microsoft-owned IP addresses. I expect that so long as the IP addresses match Microsoft's servers the onmicrosoft.com part of the domain name is accepted and that the DKIM/DMARC reports are purely for show and are not acted upon.
There's probably a whole level of authentication we are unaware of.