delete
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... described in RFCs 882(-> 1035std13 | 1034std13) and 883(-> 1035std13 | 1034std13) have been
deleted. Redesigned services may become available in the future, or the
opcodes may be reclaimed for other use.
...
... unilaterally change the data in the zone, grow new tree sections
connected to the zone, delete existing nodes, or delegate new subzones
under its zone.
...
...
d. if the response shows a servers failure or other
bizarre contents, delete the server from the SLIST and
go back to step 3.
...