Anyone know how to setup RBL in Plesk?
I've Plesk 8.3 with a Centos 5 installed on a VPS. The Plesk panel setup only few option but no RBL. I already have Plesk configured with Spamassasin over Qmail.
You probably need to install it.
Using the Plesk Update Manager, look to install "psa-qmail-rblsmtpd", it might also be referred to as some variant of "Spam Blocker for QMail" or "Real-time Blackhole List client for qmail".
After you have installed it, enable it and configure it - should be good to go.
The best advice I can give you is to use Spamdyke with qmail. It is intercepting SMTP connections before the qmail server and processes DNSBL lookups (plus other neat things).
It is very fast and it's definitely worth to a look.