sub smtp_relay {

    my $ip          = $q->param('ip')      || 'localhost';
    my $port        = $q->param('port')    || 25;
    my $timeout     = $q->param('timeout') || 30;
    my $domain      = $q->param('domain')      ||'localhost';
    my $to          = $q->param('to')      ||'you@yourdomain.com';
    my $from        = $q->param('from')      ||'nobody@nowhere.com';

    my $server = get_host_by_addr($ip);
    $ip = get_host_by_name($ip);

    my $message= "Test relay message for $server [$ip].
    You will get this message only if $server is an OPEN RELAY \015\012.\015\012
";

    print "Attempting to connect to SMTP $server [$ip] on port $port\n";

    my $sock = IO::Socket::INET->new(   PeerAddr    => $ip,
                                        PeerPort    => $port,
                                        Proto       => 'tcp',
                                        Timeout     => $timeout
                                    );
    do{ print $CONN_FAILURE; return} unless $sock;

    $sock->autoflush(1);

    my $data = getline($sock);
    sendline( $sock, "HELO $domain" );
    $data = getline($sock);
    sendline( $sock,"MAIL from: <$from>" );
    $data = getline($sock);
    sendline( $sock, "RCPT to: <$to>" );
    $data = getline($sock);
    if ($data =~ m/^550/ ) {
        sendline( $sock, 'QUIT' );
        print "</pre><h3>$server [$ip] $NOT_RELAY_SERVER</h3>";
      return $NOT_RELAY_SERVER;
    }
    sendline( $sock, 'DATA' );
    $data = getline($sock);
    sendline( $sock, $message );
    $data = getline($sock);
    sendline( $sock, 'QUIT' );
    if ( $data =~ /^250.*(?:message accepted)|(?:queued mail for delivery)/i ) {
        print "</pre><h3>$server [$ip] $IS_RELAY_SERVER</h3>";
      return $IS_RELAY_SERVER;
    }
    else {
        print "</pre><h3>$server [$ip] $POSSIBLE_RELAY</h3>";
      return $POSSIBLE_RELAY
    }

    sub sendline {
        my ( $sock, $line ) = @_;
        $sock->write($line."\015\012");
        print $line . "\n";
    }

    sub getline {
        my $sock = shift;
        my $data = '';
        while ( defined( sysread($sock, my $buffer,1) ) ) {
            $data .= $buffer;
          last if $buffer eq "\n";
        }
        print $data;
      return $data;
    }
}