Connected: An Internet Encyclopedia
2. Update Message Format

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2. Update Message Format

2. Update Message Format

The DNS Message Format is defined by [RFC1035 4.1]. Some extensions are necessary (for example, more error codes are possible under UPDATE than under QUERY) and some fields must be overloaded (see description of CLASS fields below).

The overall format of an UPDATE message is, following [ibid]:

      +---------------------+
      |        Header       |
      +---------------------+
      |         Zone        | specifies the zone to be updated
      +---------------------+
      |     Prerequisite    | RRs or RRsets which must (not) preexist
      +---------------------+
      |        Update       | RRs or RRsets to be added or deleted
      +---------------------+
      |   Additional Data   | additional data
      +---------------------+

The Header Section specifies that this message is an UPDATE, and describes the size of the other sections. The Zone Section names the zone that is to be updated by this message. The Prerequisite Section specifies the starting invariants (in terms of zone content) required for this update. The Update Section contains the edits to be made, and the Additional Data Section contains data which may be necessary to complete, but is not part of, this update.


Next: 2.1. Transport Issues

Connected: An Internet Encyclopedia
2. Update Message Format