Find the servers that should hear about a change
01DNS is the Domain Name System. A zone is a managed portion of its naming tree. Authoritative servers serve that zone’s records; a resource record, or RR, is one piece of DNS data.
In a separate configured transfer graph, primary supplies a, and a supplies b and stealth. A secondary may also be a master. There is one root and no transfer loop; these arrows represent zone-transfer dependencies, not Notify Set membership.
Source for this drawing: RFC 1996 · Read RFC source: § 2.1 and related clauses ↗
New to this? Start hereA quick picture + helpful background
A message needs an address.
Think of a packet as a small addressed envelope. Devices pass it onward; transport protocols decide what delivery promises an application gets.
Helpful first, if these ideas are unfamiliar
These pictures are analogies to help you learn. The linked RFC explains the actual rules.
Terms in this drawing
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
The SOA (Start of Authority) record names the primary master in MNAME. NS (name server) records list other authoritative servers. The primary master may, but need not, also appear in the NS set.
- The SOA (Start of Authority) record names the primary master in MNAME. NS (name server) records list other authoritative servers. The primary master may, but need not, also appear in the NS set.
- The default Notify Set is the zone’s NS server set minus the server named in SOA MNAME. An administrator can override or extend this set, including a stealth server absent from NS records.
- A server can receive a zone as a secondary and supply it as a master to others. The AXFR/IXFR zone-transfer dependency graph must have one primary master and no loops. A Notify Set is not itself that dependency graph.
Fictional picnic.example zone and documentation-only addresses. Drawings are schematic; no DNS traffic, server configuration or zone transfer is performed.
Read the RFC section ↗