Some messages with Received header containing an IP address with Bad Reputation are blocked even if the IP address has been added to Local Good Sender IPs list.
This issue occurs only when Symantec Brightmail Gateway (SBG) receives the message from one of the mail relays that is considered as one of the Internal Mail Hosts.
Symantec is aware of this issue and will update this document when a solution becomes available. It is not necessary to log a support case on this issue. Please subscribe to this article to be notified of any updates.
To avoid running into this issue, please make sure that SBG is deployed at the gateway and does not receive mail from outside world through internal mail relays.