Read the NOTIFY request and acknowledgement
02NOTIFY reuses the DNS message envelope with opcode 4. The question names the zone and asks about its SOA record; it does not carry an entire zone.
Request Authority and Additional counts should be zero in this version. If they arrive nonzero, ignore those sections rather than dropping the message for that reason. Other fields not described by this specification must be zero. No EDNS or modern-extension parser is implemented here.
Source for this drawing: RFC 1996 · Read RFC source: § 3.2 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 illustrated request has QR=0, AA=1, opcode=4, response code NOERROR, one question and QTYPE=SOA. QR distinguishes request from response; AA is the authoritative flag. ID identifies the transaction.
- The illustrated request has QR=0, AA=1, opcode=4, response code NOERROR, one question and QTYPE=SOA. QR distinguishes request from response; AA is the authoritative flag. ID identifies the transaction.
- The acknowledgement has QR=1 and the same ID and question. Its arrival completes notification to that server, not an SOA check or a zone transfer.
- Fields not otherwise described are zero and messages violating that rule must be ignored. This version sends zero Authority/Additional counts, but receivers must ignore those sections, not the whole message, when their counts are nonzero. This is an explicit compatibility exception.
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 ↗