Managing Mission - Critical Domains and DNS

Syncing zone data across secondaries

Traditionally, zonedata is kept in sync across the master and mirror nameservers via zone transfers (AXFR and IXFR). When a zone is updated, the master sends NOTIFY packets to each NS RR as well as any applicable also-notify destinations, and if the SOA serial on the master is higher, the mirrors initiate the zone transfers.

Sometimes, you see arrangements where multiple masters are utilized, especially if separate DNS operators are being employed for redundancy. Unless those disparate masters are themselves synced via some other method, such as SQL replication, this is not recommended. Doing so necessitates making any changes in the zone more than once, at each master location, and this unfailingly leads ...