Open recursors asking for random subdomains can generate bigger volume of attack, but still, they are smart and will fall back if the server is overwhelmed.<p>Even if you&#x27;re assuming 100 qps from each of the 94k recursors, that&#x27;s only 9.4M qps. And most of the recursors will notice lack of answer and will slow down &#x2F; stop the queries. In practice random subdomain attacks rarely generate more than a million qps (YMMV, there are exceptions, technical nitpics, etc).