# Postscreen
postscreen_access_list = permit_mynetworks

postscreen_dnsbl_sites = zen.spamhaus.org*3
                         b.barracudacentral.org*2
                         bl.spameatingmonkey.net*2
                         dnsbl.ahbl.org*2
                         bl.spamcop.net
                         dnsbl.sorbs.net
                         psbl.surriel.com
                         bl.mailspike.net
                         swl.spamhaus.org*-4
                         list.dnswl.org=127.[0..255].[0..255].0*-2
                         list.dnswl.org=127.[0..255].[0..255].1*-3
                         list.dnswl.org=127.[0..255].[0..255].[2..255]*-4 
postscreen_dnsbl_threshold = 3
postscreen_dnsbl_action = enforce

postscreen_greet_banner = You have to respect RFCs
postscreen_greet_action = enforce