sub IP_valid {
my $ip = shift;
    $ip =~/^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/;
    foreach ($1,$2,$3,$4){
        if ( defined $_ && $_  <256 && $_ >0) {next;}
        return 0;
    }
    return 1;
}