blacklist-database

[Andrea Bencini]

I installed spamassassin-3.0.4
I would like to test if the e-mails, MTA receives, are spam using
20_dnsbl_test.cf.
Suppose my MTA receives an e-mail [EMAIL PROTECTED] and the domain
"thisisblacklist.com" is in the database of dnsbl.njabl.org.
How do I to see if my spamassassin checks in dnsbl.njabl.org or in other
database?
In my local.cf I have
use_bayes 1
skip_rbl_checks 0
What other parameters do I have to set?
Thank
Andrea