Automatic Whitelist in Backscatter with Domain Sharing
I want to suggest if ever the domain sharing is active, the email from other mail server with the same domain should be treated as local email and automatically whitelisted or exempted from "Backscatter Protection Verification" since the IP Address was already added on domain sharing.
The problem arise when the mailing list email from the other server was rejected by the receiving server due to "550 5.1.1 Backscatter Protection detected an invalid or expired email address"
Thank you for sharing your idea with us to automatically exempt IPs from backscatter protection when they are set up for domain sharing. The best approach, in this case, is to add a notification address to the mailing list so that messages are not sent with a NULL Mail From. This can also improve the deliverability of messages on the internet and sets an address that can be notified when there are delivery issues.
With all that being said, we will look into your request for future versions.