query
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... ICMP message indicating that the port is unreachable, or until a
NOTIFY response is received from the slave with a matching query ID,
QNAME, IP source address, and UDP ...
... answer section with its local data as a "no further work needs to be
done" indication. If ANCOUNT=0, or ANCOUNT>0 and the answer section
differs from the slave's local data, then the slave should query its
known masters to retrieve the new data.
...
... reached its REFRESH interval (see []), i.e., it should query
its masters for the SOA of the zone given in the NOTIFY QNAME, and
check the answer to see if the SOA SERIAL has been incremented since
...
... a slave will receive a NOTIFY from one of its known masters even
though the rest of its known masters have not yet updated their
copies of the zone. Therefore, when issuing a QUERY for the
zone's SOA, the query should be directed at the known master who
...
... copies of the zone. Therefore, when issuing a QUERY for the
zone's SOA, the query should be directed at the known master who
was the source of the NOTIFY event, and not at any of the other
known masters. This represents a departure from [RFC1035 ...
... and AXFR/IXFRs only from its known masters, it will have an
opportunity to retry its QUERY for the SOA after each of its masters
have completed each zone update.
...
...
query ID: (new)
op: NOTIFY (4)
resp: NOERROR
...
...
query ID: (same)
op: NOTIFY (4)
resp: NOERROR
...
... This is intended to be identical to the NOTIFY request, except that
the QR bit is also set. The query ID of the response must be the
same as was received in the request.
...
... When a master server receives a NOTIFY response, it deletes this
query from the retry queue, thus completing the "notification
...
... UDP source address can
cause a slave to send spurious SOA queries to its masters,
leading to a benign denial of service attack if the forged
...
... TCP spoofing could be used against a slave server given
NOTIFY as a means of synchronizing an SOA query and UDP/DNS
...