In a DNS setup, when a secondary DNS server cannot reach the primary, which describes its behavior after a timeout?

In a DNS setup, when a secondary DNS server cannot reach the primary, which describes its behavior after a timeout?

• A. It immediately fails over to another secondary
• B. It redirects clients to the primary server
• C. It continues to answer with cached data indefinitely
• D. It will stop responding to queries after a specified period.

Answer: (D)

In DNS, secondaries rely on the primary for up-to-date zone data and use timers in the SOA to manage freshness. If the primary becomes unreachable, the secondary keeps trying to refresh, but once the expire timer elapses without a successful transfer, the data is considered stale. At that point the secondary stops acting as the authoritative source for that zone and will stop answering queries for it until contact with the primary is restored and a new transfer can occur. This behavior reflects the inability to guarantee current data without a successful refresh. It doesn’t automatically switch to another secondary, doesn’t redirect clients to the primary, and doesn’t continue indefinitely with cached data beyond the expire period.

In DNS, secondaries rely on the primary for up-to-date zone data and use timers in the SOA to manage freshness. If the primary becomes unreachable, the secondary keeps trying to refresh, but once the expire timer elapses without a successful transfer, the data is considered stale. At that point the secondary stops acting as the authoritative source for that zone and will stop answering queries for it until contact with the primary is restored and a new transfer can occur. This behavior reflects the inability to guarantee current data without a successful refresh. It doesn’t automatically switch to another secondary, doesn’t redirect clients to the primary, and doesn’t continue indefinitely with cached data beyond the expire period.