; DNS-based Blacklist servers ; Note: ; To exempt specific hostnames, IP address, or sender mail addresses ; from DNS Blacklist checking, use the ctrl/dnsbl_exempt.cfg file sbl.spamhaus.org (see http://www.spamhaus.org/) bl.spamcop.net (see http://spamcop.net/bl.shtml) spam.dnsbl.sorbs.net (see http://www.sorbs.net/faq/spamdb.shtml)