Administrator's Guide - Kerio Software Archive

16.3 Custom RulesSORBSSpam and Open Relay Blocking System (SORBS) creates and maintains set of databasesof spammer IP addresses and domain names. By default, Kerio MailServer includes twoaggregate zones of spammer databases containing all basic partial databases addressingcertain types of spammer servers:• SORBS-DNSBL — database of spammer IP addresses.• SORBS-DNSBL — database of spammer domain names.For more information on SORBS, refer to http://www.de.sorbs.net/SpamHaus SBL-XBLThe SpamHaus SBL-XBL database combines a database of spammer IP addresses witha database of illegal exploits performed by third parties:• Spamhaus Block List — SBL is a database of IP addresses of proved spammers. Theseservers are verified to prove that they really are spammers.• Spamhaus Exploit Block List — XBL is a database of IP addresses of illegal exploitsperformed by third parties, including open proxy servers, worms and viruses carryingharmful executable codes and other types of Trojan horse.For more information on SpamHAUS SBL-XBL, refer to http://www.spamhaus.org/Weighted Private Block ListWeighted Private Block List (WPBL) is a database of spammer IP addresses maintained bya committee scanning for and rating spammer servers. The database is available for free.For more information on WPBL, refer to http://www.wpbl.info/Distributed Sender Blackhole ListThere also exist several types of Distributed Sender Blackhole List (DBSL) databases. Bydefault, Kerio MailServer includes the following ones:• Distributed Sender Blackhole List — trusted — the list includes all single-stage spammerrelay servers. These servers are verified to prove that they really are spammers.• Distributed Sender Blackhole List — unconfirmed — the list includes any reports onspammer servers received. This means that it includes also servers which are nottested sufficiently for spam-sending. Therefore, it is recommended to set lower scorevalues for this blacklist.For more information on DSBL, refer to http://dsbl.org/.16.3 Custom RulesIf Kerio MailServer’s internal antispam features do not satisfy your needs, it is possible tomanually customize rules to create a suitable filter which would complement the internalsystem and increase the antispam efficiency. These rules can be defined on the Custom Rulestab.The tab consists of two sections. One contains list of rules and their definition tools. Thelatter covers settings of how messages blocked by server-defined rules would be handled.177