Postfix+Amavisd-new: "User unknown" or how not to skip emails with non-existent recipients

Question

System administration

Good day!
Actually, letters come with a non-existent recipient address and an invalid return address :)
If we send an error message, then as a result we produce spam. the recipient is invalid ... Tell me

, how in the Postfix + Amavisd-new bundle:
1. Disable sending “User unknown” messages
2. Do not accept the message at all if at least one recipient is not on the server

Answer 1

You can wrap all such mail in a separate mailbox using luser_relay and then sort it manually. But this is the treatment of appendicitis with aspirin.
In my mind, it is necessary to deal with the relay. There are two options here:

1. use the blacklist_recipients sendmail feature , thus feeding all existing users;
2. tear down sendmail, and install something like postfix with functionality similar to reject_unverified_recipient .

Answer 2

Postfix Address Verification Howto

Answer 3

Sorry, have you read www.postfix.org/BACKSCATTER_README.html ? What exactly was done according to this documentation and what did not work?

Answer 4

Yes, I read. I didn’t see a user check there, maybe I’m looking badly?

Answer 5

Everything is not right - the failure to transfer from the relay to the server goes to the relay, and the relay tries to send it to a non-existent user, for example, to yandex, and Yandex is also not a fool and refuses non-existent accounts.
I can at least re-read a ton of documents, you just drop the links.
Threat Thanks to knowledgeable comrades for the minus;)

Answer 6

If the return address is invalid, the letter will not be sent anywhere.
If valid, then some secretary receives a notification that she mistyped the address.
What is wrong? And why are we "spreading spam"?