External mail users are authenticating to the Symantec Mail Gateway (SMG) appliance for outbound mail relay via SMTP Authentication but messages delivered to some restricted internal distribution lists are rejected as coming from an anonymous rather than authenticated sender.
SMG SMTP Authentication is used solely to authenticate whether the end user is authorized to relay messages through the appliance. Once the SMG appliance accepts the mail for relay it does not do SMTP Authentication with the destination mail host and so all messages are relayed without authentication. For restricted Exchange distribution lists this means that the message is coming from an anonymous rather than authenticated connection.
This is expected behavior.
SMG does not pass through or otherwise cache SMTP Authentication credentials when delivering messages. SMTP Authention is used to determine when an external mail user has relay priveledges but all mail relayed through or delivered from the SMG appliance is done without SMTP Authentication to the downstream host.
Symantec is reviewing this issue for a potential future product enhancement. Please subscibe to this article to be notified of future updates.
Exchange Symantec Messaging Gateway
Imported Document ID: TECH168760
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