Postfix won't reject undeliverable messages

Question

I'm not shure about the wording. Maybe bouncing is the right word.

Problem is, that a local user did send a message to a non-existing domain. Now I expected that postfix will send the message back to the sender. Isn't this default behavior? And if not, what have I to do to get this working?

If someone's interesseted in my postfix configuration: Pastebin (because it's to large to post here).

The problem in simple steps:

1. james.bond@mydomain.org sends a message via mail.mydomain.org to alfred@nonexistenddomain.org
2. Mail stays in postfix' mailqueue now for over 5 days.

My intention:

• Notify the sender (james.bond@mydomain.org) that message couldn't get delivered.

Answer 1

Postfix is saving the message to try again later. You can use these parameters to change this behavior.

Be careful because remote servers using Greylisting may not accept messages if you haven't tried enough times or waited long enough.

Answer 2

You'll want to set a positive time value for delay_warning_time.

e.g.: delay_warning_time = 90m

Answer 3

The parameter you want to look at is bounce_queue_lifetime.

It seems that in your configuration it's set to 2 days, which is kind of low. Perhaps you changed it after this issue occurred? Or did you remember to reload Postfix after changing it?