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Valid messages blocked at Messaging Gateway due to no sender and no reverse DNS


Article ID: 172103


Updated On:


Messaging Gateway


Legitimate emails are being stopped by Symantec Messaging Gateway (SMG) due to the following conditions:

  • No valid sender in the envelope
  • IP address the message is coming from has no valid reverse DNS entry

Message Audit Log entries will show:

Rejected message by MTA, RDNS record fro connecting IP has no matching 'A' or 'MX' records


Recommended Solution:

The sender domain must add either an 'A' record or 'MX' record that returns the IP or IPs in question to their domain.



Disable DNS Validation for situations where RDNS exists, but 'A' or 'AAAA' does not match.


For both solutions: see Error: "554 5.7.1 Rejected message by MTA, RDNS record for connecting IP has no matching 'A' or 'MX' records"