The other thing to think about is how easy it would have been to avoid being taken down in this attack. First do not use DNS within a service. Some companies blamed other providers but in fact it was their fault for using names instead of IPs in a fixed architecture. Second, if a company is stupid enough to rely on DNS, do not rely on one DNS provider. Third, if a company did rely on DNS and had a backup DNS provider, do not wait 2 hours to switch over to the backup.
Now that this attack is history those providers that learned something for it will be easily able to thwart the next one.
Now that this attack is history those providers that learned something for it will be easily able to thwart the next one.\
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Sure...Easy Peasy.