Track the whole increment history
04Each small step may advance while its final endpoint is older than, undefined against, or equal to an earlier starting point.
The third increment is 56. All three individual steps advance, but the final label equals the original; no original-start relationship follows just from the step count.
Source for this drawing: RFC 1982 · Read RFC section 4 ↗
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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.
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Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
Newer than the immediately previous value does not imply newer than every earlier value.
- Corollary 1: a defined increment produces a serial greater than or equal to its start, equal only for zero. Corollary 2: after a nonzero defined n and another defined m, no general older/newer conclusion follows relative to the original start, although the result is known not equal to it (§§4.1–4.2). This is a limit on a general inference, not a claim that every particular endpoint comparison is undefined.
- The published eight-bit chain 100→200→44 adds 100 twice. Each new serial is greater than its immediate predecessor, yet 44 is less than the original 100. In fact 100<200,200<44,44<100 forms a cycle under serial comparison. Sorting every possible serial as if this were an ordinary transitive comparator is unsound (§§3.2,4.2,5.2).
- Two defined increments of 64 from zero reach 128, an undefined comparison against zero. In contrast 0→60→120 has total increment 120 within the allowed 127 limit: Corollary 4 guarantees the final result is greater than the start. A small per-step increment alone is insufficient; the sum matters (§§4.2,4.4).
- Corollary 3 says a further increment leaves no generally known relationship to the original start. Chosen chain 0→100→200→0 uses increments 100,100,56, all individually defined; the last endpoint equals the original. These are offline arithmetic examples, not a prescribed DNS reset procedure (§4.3).
Fictional offline arithmetic and DNS observations. Small spaces illustrate the rule; DNS SOA uses 32 bits. Not a DNS implementation, transfer protocol, operational reset recipe or authenticity check.
Read the RFC section ↗