Connected: An Internet Encyclopedia
3.6. Zone Identity
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RFC 2136
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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:
- Each update operation.
- 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.
- 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.
- 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