Email Security: How to troubleshoot NDR's.
03/26/2020 1029 11287
I do not receive NDR's, How can I see what message was rejected?
In Email Security go to the Manage | Server | Advanced | Download System/Log Files | pmta:mta-log and download the MTA hourly log for the time the original message was sent.
Keep in mind that these are logged in GMT so you will need to add hours according to the time zone you are in.
Listed below is the general ESMTP response codes you may see listed in an SMTP conversation.
ESMTP STATUS CODE
System status, or system help reply
(Information on how to use the receiver or the meaning of a particular non-standard command; this reply is useful only to the human user)
Service closing transmission channel
Requested mail action okay, completed
User not local; will forward to
Start mail input; end with "."
Service not available, closing transmission channel
(This may be a reply to any command if the service knows it must shut down)
Requested mail action not taken: mailbox unavailable
(E.g., mailbox busy)
Requested action aborted: local error in processing
Requested action not taken: insufficient system storage
Syntax error, command unrecognized
(This may include errors such as command line too long)
Syntax error in parameters or arguments
Command not implemented
Bad sequence of commands
Command parameter not implemented
Requested action not taken: mailbox unavailable
(E.g., mailbox not found, no access)
User not local; please try <....>
Requested mail action aborted: exceeded storage allocation
Requested action not taken: mailbox name not allowed
(E.g., mailbox syntax incorrect)
For specific codes for Microsoft Exchange please see their KB: http://support.microsoft.com/kb/284204
There are also many other documents in the Microsoft KB depending on the NDR you are seeing.