Mail listener ping-ponging with mailer-daemon

Summary

The gitlab e-mail listener responds to a mailer-daemon 'undelivered Mail' message with a 'could not be processed'. The mailer-daemon then responds with a 'mailbox not found' (mailer-daemon). This produces high traffic and a never ending ping-pong game.

Steps to reproduce

Just send an e-mail with an e-mail-address that does not exist to your gitlab email.

What is the current bug behavior?

The gitlab server and the mail server are sending emails between each other without stopping.

What is the expected correct behavior?

Gitlab should notice that an e-mail comes from 'mailer-daemon' and should not respond to it.

Relevant logs and/or screenshots

Possible fixes

As I said, Gitlab should ignore e-mail coming from a 'mailer-daemon' or smartly check if he previously had a 'could not deliver' with a certain e-mail address and then not send the email.