If RBL flags email as spam, whitelisting in ISPConfig doesn't matter, correct?

[friday]

I just want to verify this for a client.

If a email comes in that does not pass the RBL check (via spamhaus), it is immediately removed before it has a chance to go to spamassassin/clamav. The whitelist/blacklist in ISPConfig only really applies to spamassassin and what happens to emails after they pass the postfix checks (RBL checks).

I'm correct in this, right?

[till]

Yes thats correct.

But the email is not immediately remocved, instead it is rejected. Rehected measn that the email server has not accepted it so that the sender is notified by its own mailserver about the rejection.