I can't test (no win32 here), but I would replace the ping command with Net::Ping

use Net::Ping;

...

sub controlla{
    my $ok = 0;
    my $p = Net::Ping->new("icmp");
    my $tries = $conteggio;
    while ($tries-- > 0) {
        $++ok if $p->ping($host);
    }
    return $ok;
}
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