Techniques are provided for increasing the efficiency and efficacy of DNS clients. In one technique, DNS clients log information about performance of one or more DNS servers that the DNS clients use to resolve DNS resolution requests. The DNS clients send, to a control server, performance data regarding the DNS resolution requests and/or subsequent connections to servers associated with resolved domain names. Based on the performance data, the control server sends, to one or more DNS clients, configuration data that adjusts the configuration of the DNS clients. For example, if a particular DNS server is taking a considerable amount of time to resolve DNS resolution requests from one or more DNS clients, then the control server may send, to a plurality of DNS clients, configuration data that indicates a different set of one or more DNS servers for the plurality of DNS clients to contact for subsequent DNS resolution requests.