sub ValidateMasks() {
    my $mask = shift;
    return 0 if !defined $mask;

    my $binary_rep;
    my @octets = split (/\./, $mask);
    for my $octet (@octets) {
        $binary_rep .= substr(unpack("B32", pack("N", $octet)), -8);
    }
    return $binary_rep =~ /^0*1*$/;
}