diff --git a/modoboa_installer/scripts/files/postfix/main.cf.tpl b/modoboa_installer/scripts/files/postfix/main.cf.tpl
index 0123e60..1be9ea5 100644
--- a/modoboa_installer/scripts/files/postfix/main.cf.tpl
+++ b/modoboa_installer/scripts/files/postfix/main.cf.tpl
@@ -142,7 +142,7 @@ postscreen_blacklist_action = enforce
 
 # Use some DNSBL
 postscreen_dnsbl_sites = 
-	zen.spamhaus.org*3
+	zen.spamhaus.org=127.0.0.[2..11]*3
 	bl.spameatingmonkey.net*2
 	bl.spamcop.net
 	dnsbl.sorbs.net