I added rbl in postfix, but with some rbl testing server provided by http://www.crynwr.com/spam/
I still receive a junk mail sent from their testing mail
smtpd_sender_restrictions =
reject_unknown_sender_domain,
smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated reject_unauth_destination check_relay_domains reject_rhsbl_client zen.spamhaus.org reject_rhsbl_client bl.spamcop.net