The present disclosure generally relates to a failover management service that can continuously monitor attributes of regional network resources to characterize resource availability per region. The failover management service associates the regional resource availability information with a set of hash values in which each individual hash value is representative a concatenation of a resource identifier and a client identifier associated with one or more individual clients. For individual hash values, the failover management service associates failover information, which is propagated to a DNS service. If a network-resource becomes unavailable, clients can transmit DNS queries including a hash value that discovers the appropriate failover information for the specific network-based resource and client device.