[Triple_Nothing]

Wow. I am just making a list of topics on my own. :-/

Well, I guess the basic is letters hanging in SMTP and not sending. If the message is sent from an internal connection w/o AUTH, it is successful. If the message is sent from client software, StartTLS or such grants them privilege and the letter arrives in the SMTP queue, however, never sends. It appears to just sit in the queue. I know the quote kinda gives a heads up, but why would that only apply to a sent item from a remote computer, but not a local outbound?

Our system has detected that this message is 421-4.7.0 suspicious due to the very low reputation of the sending IP address. 421-4.7.0 To protect our users from spam, mail sent from your IP address has 421-4.7.0 been temporarily rate limited.

mail.log clip: http://projects.hellzoneinc.com/devs...ail-980898.txt

Wouldn't the whole fact the user's client must log in to send kinda avoid this?

[requinix]

So the queue is running, it's just that messages aren't sending quickly because you're being rate limited?

The internet doesn't know about your mail server. The servers out there don't necessarily trust you. Doesn't matter how your users authenticated (which they wouldn't even know about in the first place), as far as they know you're a spammer.

The best first step you can take is set up SPF and DKIM. They will indicate that your mail server is trusted when it comes to sending for your domain.

[Doug G]

If you have root shell access, maybe postfix's postqueue or postsuper utilities can help identify the problem.

[Triple_Nothing]

Well, at least the issue wasn't truly on my side. Once I got home from work, I noticed all went through. SPF/DKIM was planned due to alerts/notes in DNS checks/tests, but just being delayed. It all works, so troubleshooting is done. The only thing I'm a bit off with in my head is why a letter sent front the server's console has been successfully sent/accepted right away, but a letter sent from client software has been delayed. Used the same from/to addresses. No issue, tho. Thanks for any comments.

[requinix]

Because of rate limiting. If you send one email, it'll probably go through fine. If you send 10 emails in a minute, the first might go through but the 10th might not.