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Updated Dec 08, 2023
Version 10.0
Blog Post
Hello Arindam_Thokder,
well, It's pretty clear that there is no NDR when Remote Domain is matched. What I don't understand is why "it comes first". I was expecting the Outbound spam filter policy to take precedence considering that:
- The sender receives an NDR (from the outbound spam filter), but only when ForwardingAddress or ForwardingSmtpAddress are used and not when it setup Inbox Rule forwarding.
- The outbound spam filter policy 'blocks all types of auto forwarding including ForwardingAddress and ForwardingSmtpAddress mailbox parameters'. I would expect that Inbox Rules would fall under this case (like ForwardingAddress or ForwardingSmtpAddress cases).
The table is pretty useful, but I wasn't able to deduce which implementation type has the priority from it.
Allowing automatic forwarding in Remote Domain (leaving all the other as they are - look at my first post) will result in NDR send back from Mail flow rule to the sender when Inbox Rule is used.
What I have learned:
- Remote Domain comes first
- When ForwardingAddress or ForwardingSmtpAddress are in use Outbound spam filter policy is matched first (instead of Mail flow rule)
- When Inbox Rule is in use, Mail flow rule is matched first (instead of Outbound spam filter policy)
Does it sound good ?
Thank you again,
Luca