postfix rbl checks

[Gareth]

I have been checking the RBL stats using mailwatch and the NJABL one
looks like it will reject about 50% of the spam we receive with no false
positives.

In my postfix configuration I had the line :-

smtpd_recipient_restrictions = permit_mynetworks,
reject_unauth_destination, reject_unknown_recipient_domain,
reject_unverified_recipient

I changed this to :-

smtpd_recipient_restrictions = permit_mynetworks,
reject_unauth_destination, reject_unknown_recipient_domain,
reject_unverified_recipient, reject_rbl_client dnsbl.njabl.org

However after restarting postfix it is not working. Spam is still being
accepted and mailscanner is matching some against the NJABL RBL.

Any ideas what is going wrong?

Thanks
Gareth