Abstract: This disclosure describes systems, methods, and apparatus for sharing DNS answers between DNS server systems within a DNS cluster, between proxy servers, and/or between DNS server systems of different DNS clusters. When a DNS answer is obtained by a DNS server system, the answer can be shared with peer DNS server systems within a same DNS cluster or with DNS server systems having a logical relation to the first DNS server system (e.g., geographic relationship), but being in different DNS clusters. Proxy servers may also mediate communication between a client and the DNS clusters. These proxies can also include the ability to share DNS answers between each other.

Abstract: This disclosure describes systems, methods, and apparatus to protect users of the Internet from DNS outages. In particular, an outage avoidance system is provided that includes query processing, outage avoidance processing, and a local cache, all configured to extend the TTL of expired answers to DNS queries or to ignore the expiration of an answer's TTL value, and thereby provide the expired answer in response to a client request when a DNS server is unable to obtain an answer from a remote DNS server.