README.dnsbl

Code and logic from rblsmtpd and qmail-dnsbl patch http://qmail-dnsbl.sourceforge.net/

-added support for whitelists, TXT and A queries, configurable return codes 451 or 553 with custom messages

  # - default file control/dnsbllist can be overridden with env variable DNSBLLIST
  # - if DNSBLSKIP env variable is set, qmail-smtpd skips the rbl check
  # - if control/dnsblfailclosed or DNSBLFAILCLOSED are defined, qmail-smtpd considers the source ip as blacklisted even in case of lookup failures (check rblsmtpd man page for more details)
  # - support for environment variable RBLSMTPD (check rblsmtpd man page for more details)
  # - dnsbllist can contain empty lines and comments with '#' at start or end of lines; leading and trailing spaces are automatically removed

CONTROL FILES

dnsbllist
            A list of dnsbl providers that qmail-smtpd checks to identify blacklisted ip addresses.

            Exception:  If  the  environment  variable DNSBLSKIP is set, qmail-smtpd ignores dnsbllist, and the dnsbl check is not performed.  The check is skipped even if
            some other authentication method succedeed and authorized the client to relay (smtp-auth or tls client certificate), or if RELAYCLIENT enviromnent variable  is
            set.