TCP/IP Tutorial and Technical Overview - IBM Redbooks

456 TCP/IP Tutorial and Technical Overview
6 Name error. A name exists when it should not.
7 RRset error. A resource record set exists when it should
not.
8 RRset error. A resource record set specified does not
exist.
9 Zone Authority error. The server is not authoritative for
the zone specified.
10 Zone error. A name specified in the Prerequisite or
Update sections is not in the zone specified.
ZO count The number of RRs in the Zone section.
PR count The number of RRs in the Prerequisite section.
UP count The number of RRs in the Update section.
AD count The number of RRs in the Additional information section.
Zone section This section is used to indicate the zone of the records that are
to be updated. As all records to be updated must belong to the
same zone, the zone section has a single entry specifying the
zone name, zone type (which must be SOA), and zone class.
Prerequisite section
This section contains RRs or RRsets that either must, or must
not, exist, depending on the type of update.
Update section This section contains the RRs, RRsets, or both that are to be
added to or deleted from the zone.
Additional information section
This section can be used to pass additional RRs that relate to
the update operation in process.
For further information about the UPDATE message format, refer to RFC 2136.
12.2.2 Incremental zone transfers in DDNS
RFC 1995 introduces the IXFR DNS message type, which allows incremental
transfers of DNS zone data between primary and secondary DNS servers. In
other words, when an update has been made to the zone data, only the change
has to be copied to the other DNS servers that maintain a copy of the zone data,
rather than the whole DNS database (as is the case with the AXFR DNS
message type).
The format of an IXFR query is exactly that of a normal DNS query, but with a
query type of IXFR. The response’s answer section, however, is made up of
difference sequences.