[SOLVED] NDR's for Non-Existent Addresses

[thedab101]

Hello,
I'm having another problem with PMG not delivering NDR's to senders who email addresses that don't exist on my mail server (Exchange).

Exchange itself sends NDR's. I've configured PMG to "Verify Recipients" (with SMTP error 550), and to filter before queue. Send NDR's on Blocked Emails is also enabled.
When I test from a gmail account to an address that doesn't exist, I don't get an NDR. The queue shows the email inbound and says it's been accepted, but there's no mailbox to accept the message itself. I'm confused why that's happening, but I'm much more concerned about the NDR's not getting delivered.

Is there a setting or configuration I've missed?
Thanks

 

[Stoiko Ivanov]

Please share the logs of such an transaction (it's usually a lot easier to explain with some examples)

My guess - is that you have not configured Exchange to properly support recipient verification (it needs some specific configuration to really reply with a 5xx error-code after the RCPT TO command) - once this works PMG will reply with 5xx to the sending server (gmail) after RCPT TO (and gmail should notify the sender about this)

 

[thedab101]

Please share the logs of such an transaction (it's usually a lot easier to explain with some examples)

My guess - is that you have not configured Exchange to properly support recipient verification (it needs some specific configuration to really reply with a 5xx error-code after the RCPT TO command) - once this works PMG will reply with 5xx to the sending server (gmail) after RCPT TO (and gmail should notify the sender about this)

Thanks for your quick response.
I was able to configure Recipient Filtering on Exchange: messages sent to non-existent addresses are showing up as bounced in the tracking centre as expected. I'm still, however, not getting the NDR's to the sender.

Will the tracking centre show whether or not a message was sent? Because I don't see any indication of this in the log entry. I just want to know what information I should include here to help diagnose the problem.

Thanks again for your very quick response.

 

[Stoiko Ivanov]

Will the tracking centre show whether or not a message was sent? Because I don't see any indication of this in the log entry. I just want to know what information I should include here to help diagnose the problem.

a NDR is usually not sent out - because PMG simply replies with 5xx to the RCPT TO command (then it's the sending server's obligation to notify the sender (by NDR)).
However to check this you need to check for mails with empty sender (NDR's have an empty sender)

In general - if in doubt always check the syslog or mail.log (/var/log/syslog, /var/log/mail.log) - in case the tracking center is not catching the relevant information

I hope this helps!

 

[thedab101]

Very helpful. Thanks Stoiko.