Case creation by incoming email: Bouncing responses to incoming span create thousands of bogus cases and sever overload

We recently managed to get the automatic case creation working for an address like on a customer SuiteCRM server. After several days, suddenly both the SuiteCRM and the E-Mail Server server were overloaded and we realized that there were thousands of cases created within a few hours.

Closer inspection revealed that incoming spam from various invalid e-mail addresses automatically created cases, which triggered response e-mails to be sent to invalid e-mail addresses that bounced, with the bounce response creating a new case, which then triggered another response that bounced again - and so on.

I’m sure that other people have come across this before and there must be a best practice to avoid this. Unfortunately, I’ve searched and haven’t found anything.
Any help would be appreciated!

Thanks in advance.

P.S. The customer is using a Zimbra 8.6 commercial messaging server, which uses Postfix.

Hi @rholighaus,

Did you found anything regarding this issue… even we are facing the same .

Thank you.