qpsmtpd/plugins/rcpt_ok

# this plugin checks the standard rcpthosts config
#
# It should be configured to be run _LAST_!
#
use Qpsmtpd::DSN;

sub hook_rcpt {
  my ($self, $transaction, $recipient, %param) = @_;
  my $host = lc $recipient->host;

  my @rcpt_hosts = ($self->qp->config("me"), $self->qp->config("rcpthosts"));
  
  # Allow 'no @' addresses for 'postmaster' and 'abuse'
  # qmail-smtpd will do this for all users without a domain, but we'll
  # be a bit more picky.  Maybe that's a bad idea.
  my $user = $recipient->user;
  $host = $self->qp->config("me")
    if ($host eq "" && (lc $user eq "postmaster" || lc $user eq "abuse"));
  
  # Check if this recipient host is allowed
  for my $allowed (@rcpt_hosts) {
    $allowed =~ s/^\s*(\S+)/$1/;
    return (OK) if $host eq lc $allowed;
    return (OK) if substr($allowed,0,1) eq "." and $host =~ m/\Q$allowed\E$/i;
  }

  my $more_rcpt_hosts = $self->qp->config('morercpthosts', 'map');
  return (OK) if exists $more_rcpt_hosts->{$host};

  if ( $self->qp->connection->relay_client ) { # failsafe
    return (OK);
  }
  else {
    # default of relaying_denied is obviously DENY, 
    # we use the default "Relaying denied" message...
    return Qpsmtpd::DSN->relaying_denied();
  }
}