Isn&#x27;t the O(n^2) operation described in that thread happening only when the hosts file gets updated, and not with every DNS lookup?   I would imagine even sequentially searching a local list of 350,000 entries, like the post describes, would still be extremely fast in the context of loading a web page.<p>But, that said, there can be a huge difference between how one might think things should work and what actually happens.