Which statement correctly describes the purpose of DNS zone transfers?

• A. To replicate DNS zone data between primary and secondary servers.
• B. To improve DNS query performance.
• C. To enable dynamic updates.
• D. To reduce DNS traffic.

Answer: (D)

DNS zone transfers are the process by which DNS zone data is replicated from a primary (master) server to secondary (slave) servers. This replication ensures that all authoritative servers for a zone have consistent data, which supports high availability and fault tolerance. If the primary server becomes unavailable, secondary servers can still respond to queries using their local copies.

Zone transfers can be full transfers (bringing over the entire zone) or incremental transfers (only the changes since the last transfer). They use mechanisms like AXFR for full transfers and IXFR for incremental transfers. This is about keeping copies in sync across servers, not about speeding up client queries directly, and it’s not the mechanism for dynamic updates or reducing inter-server or client traffic.