A secondary can serve its transferred zone until refresh and expiry rules require a newer copy or stop service.

Zone transfer copies authoritative data under explicit authorization and serial rules

AXFR transfers a complete DNS zone so another server or authorized client can obtain its data. A secondary can then answer authoritatively from its local copy. The protocol does not magically identify callers as legitimate authoritative servers: access control decides who may transfer. A zone is also a defined authority boundary, not every record in every delegated child zone or the organization’s entire DNS namespace. ...

December 5, 2027 · 7 min · XB Field Notes