--- a/dnsbl.conf	Sat Mar 25 09:47:08 2006 -0800
+++ b/dnsbl.conf	Sat Apr 08 10:06:09 2006 -0700
@@ -1,3 +1,32 @@
+context main-default {
+    // outbound dnsbl filtering to catch our own customers that end up on the sbl
+    dnsbl   local   blackholes.five-ten-sg.com  "Mail from %s rejected - local; see http://www.five-ten-sg.com/blackhole.php?%s";
+    dnsbl   sbl     sbl-xbl.spamhaus.org        "Mail from %s rejected - sbl; see http://www.spamhaus.org/query/bl?ip=%s";
+    dnsbl   dul     dul.dnsbl.sorbs.net         "Mail from %s rejected - dul; see http://www.sorbs.net/lookup.shtml?%s";
+    dnsbl_list  local sbl dul;
+
+    // outbound content filtering to prevent our own customers from sending spam
+    content on {
+        filter    sbl-xbl.spamhaus.org        "Mail containing %s rejected - sbl; see http://www.spamhaus.org/query/bl?ip=%s";
+        uribl     multi.surbl.org             "Mail containing %s rejected - surbl; see http://www.rulesemporium.com/cgi-bin/uribl.cgi?bl0=1&domain0=%s";
+        #uribl    black.uribl.com             "Mail containing %s rejected - uribl; see http://l.uribl.com/?d=%s";
+        ignore    { include "hosts-ignore.conf"; };
+        tld       { include "tld.conf"; };
+        cctld     { include "cctld.conf"; };
+        html_tags { include "html-tags.conf"; };
+        html_limit on 20 "Mail containing excessive bad html tags rejected";
+        html_limit off;
+        host_limit on 20 "Mail containing excessive host names rejected";
+        host_limit soft 20;
+    };
+
+    // backscatter prevention - don't send bounces for mail that we accepted but could not forward
+    // we only send bounces to our own customers
+    env_from unknown {
+        "<>"    black;
+    };
+};
+
 context main {
     dnsbl   local   blackholes.five-ten-sg.com  "Mail from %s rejected - local; see http://www.five-ten-sg.com/blackhole.php?%s";
     dnsbl   sbl     sbl-xbl.spamhaus.org        "Mail from %s rejected - sbl; see http://www.spamhaus.org/query/bl?ip=%s";