Forum Discussion
DKIM for O365 Relay (On-premise SMTP server)
Replying to old topic...
Walked into this also, but my guess is that this is normal behaviour. You allready validated the recipient by creating a reveive connector for. Thus DKIM not applied.
Try relaying to a mail partner (external recipient). My guess is that DKIM applies to that one !
Jan Anne Bijlsma
You're right.
On-Prem Exchange SMTP relay to O365 DKIM=noneOn-Prem Exchange SMTP relay to External such as gmail DKIM=pass
My issue, is ExchangeOnlineProtection is marking On-Prem to O365 as SPAM (5). I figured that by adding DKIM the spam rating would likely reduce.
Not wanting to whitelist the on-prem exchange server for the SPAM filter, I'll look at switching from anonymous relay to authenticated to try and lower the spam confidence level...- did you ever find a workaround to O365 DKIM=none?
