sub portAlive {
	my $proto = getprotobyname('tcp');
	my $iaddr = inet_aton($host);
	my $paddr = sockaddr_in($port, $iaddr);
	
	socket(SOCKET, PF_INET, SOCK_STREAM, $proto) || warn "socket: $!";
	
	eval {
	  local $SIG{ALRM} = sub { die "timeout" };
	  alarm($timeout);
	  connect(SOCKET, $paddr) || error();
	  alarm(0);
	};
	
	if ($@) {
	  close SOCKET || warn "close: $!";
	  # print "$hostname is NOT listening on tcp port $portnumber.\n";
	  return 0;
	}
	else {
	  close SOCKET || warn "close: $!";
	  # print "$hostname is listening on tcp port $portnumber.\n";
	  return 1;
	}
}