Timeouts would presumably be taken care of when setting up the proxies. Major DNS providers are used to getting DDoS'ed, and will typically be fine (not always,

Timeouts would presumably be taken care of when setting up the proxies. Major DNS providers are used to getting DDoS'ed, and will typically be fine (not always, but it's a lot harder to drop them than to drop any random server). I agree that there's probably a way to break things; but an attacker would need to actually do some work for most of them (e.g. create lots of accounts?)