May 26, 2018
Net::DNSBL::MultiDaemon - multi DNSBL prioritization
NetDNSBLMultiDaemon is the Perl module that implements the multi_dnsbl daemon.
multi_dnsbl is a DNS emulator daemon that increases the efficacy of DNSBL look-ups in a mail system. multi_dnsbl may be used as a stand-alone DNSBL or as a plug-in for a standard BIND 9 installation. multi_dnsbl shares a common configuration file format with the MailSpamCannibal sc_BLcheck.pl script so that DNSBL’s can be maintained in a common configuration file for an entire mail installation.
Because DNSBL usefulness is dependent on the nature and source of spam sent to a specific site and because sometimes DNSBL’s may provide intermittant service, multi_dnsbl interrogates them sorted in the order of greatest successful hits. DNSBL’s that do not respond within the configured timeout period are not interrogated at all after 6 consecutive failures, and thereafter will be retried not more often than once every hour until they come back online. This eliminates the need to place DNSBL’s in a particular order in your MTA’s config file or periodically monitor the DNSBL statistics and/or update the MTA config file.