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Notes for BIND 9.17.6
---------------------

New Features
~~~~~~~~~~~~

- Add a new ``rndc`` command, ``rndc dnssec -rollover``, which triggers
  a manual rollover for a specific key. [GL #1749]

- Add a new ``rndc`` command, ``rndc dumpdb -expired``, which dumps the
  cache database, including expired RRsets that are awaiting cleanup, to
  the ``dump-file`` for diagnostic purposes. [GL #1870]

Removed Features
~~~~~~~~~~~~~~~~

- The ``glue-cache`` *option* has been marked as deprecated. The glue
  cache *feature* still works and will be permanently *enabled* in a
  future release. [GL #2146]

Feature Changes
~~~~~~~~~~~~~~~

- DNS Flag Day 2020: The default EDNS buffer size has been changed from
  4096 to 1232 bytes, the EDNS buffer size probing has been removed, and
  ``named`` now sets the DF (Don't Fragment) flag on outgoing UDP
  packets. According to measurements done by multiple parties, this
  should not cause any operational problems as most of the Internet
  "core" is able to cope with IP message sizes between 1400-1500 bytes;
  the 1232 size was picked as a conservative minimal number that could
  be changed by the DNS operator to an estimated path MTU minus the
  estimated header space. In practice, the smallest MTU witnessed in the
  operational DNS community is 1500 octets, the maximum Ethernet payload
  size, so a useful default for maximum DNS/UDP payload size on reliable
  networks would be 1400 bytes. [GL #2183]

Bug Fixes
~~~~~~~~~

- ``named`` reported an invalid memory size when running in an
  environment that did not properly report the number of available
  memory pages and/or the size of each memory page. [GL #2166]

- With multiple forwarders configured, ``named`` could fail the
  ``REQUIRE(msg->state == (-1))`` assertion in ``lib/dns/message.c``,
  causing it to crash. This has been fixed. [GL #2124]

- ``named`` erroneously performed continuous key rollovers for KASP
  policies that used algorithm Ed25519 or Ed448 due to a mismatch
  between created key size and expected key size. [GL #2171]

- Updating contents of an RPZ zone which contained names spelled using
  varying letter case could cause some processing rules in that RPZ zone
  to be erroneously ignored. [GL #2169]
