when serve-stale is enabled, NXDOMAIN cache entries are no longer
preserved after the normal negative cache TTL, in order to reduce
unnecessary cache memory consumption.
(cherry picked from commit f1485ca145)
when serve-stale is enabled, NXDOMAIN cache entries are no longer
preserved after the normal negative cache TTL, in order to reduce
unnecessary cache memory consumption.
(cherry picked from commit f1485ca145)