I just put this up quickly because someone asked a question related to this on the mailing list.

=head1 NAME

spamtrap - handle spamtrap addresses

=head1 DESCRIPTION

xxx

=head1 CONFIGURATION

xxx

=head1 AUTHOR

Written by Johan Almqvist

=cut

use Mail::Address;

sub register {
  my ($self, $qp, @args) = @_;

  if (@args > 0) {
    $self->{_spamtrap} = $args[0];
    if (@args > 1) {
      $self->log(LOGWARN, "WARNING: Ignoring additional arguments.");
    }
    $self->register_hook("rcpt", "rcpt_handler");
    $self->register_hook("data_post", "data_handler");
  }
  else {
    $self->log(LOGWARN, "WARNING: No spamtrap address provided");  
  }
}

sub rcpt_handler {
	my ($self, $transaction, $rcpt) = @_;

	my $addr = lc $rcpt->address or return DECLINED;
	my $host = lc $rcpt->host or return DECLINED;
	my $user = lc $rcpt->user or return DECLINED;

	for my $h ($self->qp->config('spamtraps')) {
		next unless $h;
		$h = lc $h;

		if ($addr eq $h or $host eq $h) {
			$transaction->notes('whitelist', 1);
			$transaction->notes('denysoft_greylist', 0);
			$transaction->notes('spamtrap', 1);
			$self->log(2,"Recipient $addr is a spamtrap");
			return (OK, 'User is a spam trap. May you burn in hell.');
		}
	}
	DECLINED;
}

sub data_handler {
	my ($self, $transaction) = @_;

	my @spamtrap = Mail::Address->parse($self->{_spamtrap});
	if ($transaction->notes('spamtrap')) {
		$transaction->recipients(@spamtrap);
		return OK;
	}
	return DECLINED;
}