Connected: An Internet Encyclopedia
3.6. Zone Identity

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3.6. Zone Identity

3.6. Zone Identity

If the zone's SOA SERIAL is changed by an update operation, that change must be in a positive direction (using modulo 2**32 arithmetic as specified by [RFC1982]). Attempts to replace an SOA with one whose SERIAL is less than the current one will be silently ignored by the primary master server.

If the zone's SOA's SERIAL is not changed as a result of an update operation, then the server shall increment it automatically before the SOA or any changed name or RR or RRset is included in any response or transfer. The primary master server's implementor might choose to autoincrement the SOA SERIAL if any of the following events occurs:

  1. Each update operation.

  2. A name, RR or RRset in the zone has changed and has subsequently been visible to a DNS client since the unincremented SOA was visible to a DNS client, and the SOA is about to become visible to a DNS client.

  3. A configurable period of time has elapsed since the last update operation. This period shall be less than or equal to one third of the zone refresh time, and the default shall be the lesser of that maximum and 300 seconds.

  4. A configurable number of updates has been applied since the last SOA change. The default value for this configuration parameter shall be one hundred (100).

It is imperative that the zone's contents and the SOA's SERIAL be tightly synchronized. If the zone appears to change, the SOA must appear to change as well.


Next: 3.7. Atomicity

Connected: An Internet Encyclopedia
3.6. Zone Identity