NAME

       Mail::Milter::Module::ConnectDNSBL - milter to accept/reject connecting hosts matching
       DNSBLs

SYNOPSIS

           use Mail::Milter::Module::ConnectDNSBL;

           my $milter = new Mail::Milter::Module::ConnectDNSBL('foo.spamlist.dom');

           my $milter2 = &ConnectDNSBL('foo.spamlist.dom'); # convenience

           $milter2->set_message('Connections from %A disallowed');

DESCRIPTION

       This milter module rejects any connecting host whose IPv4 address matches a given DNS
       Blocking List (DNSBL).  It can also function as a whitelisting Chain element; see
       "accept_match()".

       The check used by this module is a simple "A" record lookup, via the standard
       "gethostbyname" lookup mechanism.  This method does not require the use of Net::DNS and is
       thus typically very fast.

       (Note:  If the connecting host is not using IPv4, this module will simply be a passthrough
       using SMFIS_CONTINUE.)

METHODS

           new(DNSBL)

           new(DNSBL, MATCHRECORD[, ...])

           new(DNSBL, SUBREF)

           Creates a ConnectDNSBL object.  DNSBL is the root host hierarchy to use for lookups.
           Three methods of matching can be used:

           If no additional arguments are provided, the match succeeds if there is any address
           entry present for the DNSBL lookup; the values are not examined.

           If one or more MATCHRECORD values are supplied, they are string representations of
           IPv4 addresses.  If any of these match record values is the same as any address record
           returned by the DNSBL lookup, the match succeeds.

           If a SUBREF (reference to a subroutine; may be an anonymous inline "sub{}") is
           supplied, it is called for each of the address records returned by the DNSBL lookup.
           The subroutine should return 0 or undef to indicate a failed match, and nonzero to
           indicate a successful match.  The subroutine receives a binary-encoded four byte
           scalar that should be transformed as needed with "inet_ntoa()" or "unpack".

           accept_match(FLAG)

           If FLAG is 0 (the default), a matching DNSBL will cause the connection to be rejected.

           If FLAG is 1, a matching DNSBL will cause this module to return SMFIS_ACCEPT instead.
           This allows a "ConnectDNSBL" to be used inside a "Mail::Milter::Chain" container (in
           accept_break(1) mode), to function as a whitelist rather than a blacklist.

           This method returns a reference to the object itself, allowing this method call to be
           chained.

           ignore_tempfail(FLAG)

           If FLAG is 0 (the default), a DNSBL lookup which fails the underlying DNS query will
           cause the milter to return a temporary failure result (SMFIS_TEMPFAIL).

           If FLAG is 1, a temporary DNS failure will be treated as if the lookup resulted in an
           empty record set (SMFIS_CONTINUE).

           This method returns a reference to the object itself, allowing this method call to be
           chained.

           set_message(MESSAGE)

           Sets the message used when rejecting connections.  This string may contain the
           substring %A, which will be replaced by the matching IPv4 address, or %L, which will
           be replaced by the name of the matching DNSBL.

           This method returns a reference to the object itself, allowing this method call to be
           chained.

BUGS

       In Sendmail 8.11 and 8.12, a milter rejection at "connect" stage does not allow the reply
       message to be set -- it simply becomes "not accepting messages".  However, this module
       still attempts to set the reply code and message in the hope that this will be fixed.

AUTHOR

       Todd Vierling, <tv@duh.org> <tv@pobox.com>

SEE ALSO

       Mail::Milter::Object

POD ERRORS

       Hey! The above document had some coding errors, which are explained below:

       Around line 79:
           You can't have =items (as at line 91) unless the first thing after the =over is an
           =item