sub Is_Host_Alive
{
    my ($host) = @_;
    my $tmp_syn=Net::Ping->new("syn");
    $tmp_syn->ping($host);
    if(!$tmp_syn->ack){
     	 # print "$host unreachable \n";
        $tmp_syn->close;
        return 0;
    }
    $tmp_syn->close;
    return 1;
}