Introduction

   BIND 9.7.6-P4 is the latest production release of BIND 9.7.6 (BIND
   9.7.7 is also available for download, and is the latest production
   release of BIND 9.7).

   This document summarizes changes from BIND 9.7.5 to BIND 9.7.6-P4.
   Please see the CHANGES file in the source code release for a
   complete list of all changes.

Download

   The latest versions of BIND 9 software can always be found on our
   web site at http://www.isc.org/downloads/all. There you will find
   additional information about each release, source code, and
   pre-compiled versions for Microsoft Windows operating systems.

Support

   Product support information is available on
   http://www.isc.org/support for paid support options.  Free support
   is provided by our user community via a mailing list.  Information
   on all public email lists is available at
   https://lists.isc.org/mailman/listinfo.

Security Fixes

*  A deliberately constructed combination of records could cause named
   to hang while populating the additional section of a response.
   [RT #31090]

*  Prevents a named assert (crash) when queried for a record whose
   RDATA exceeds 65535 bytes.  [RT #30416]

*  Prevents a named assert (crash) when validating caused by using
   "Bad cache" data before it has been initialized.  [RT #30025] 

*  A condition has been corrected where improper handling of
   zero-length RDATA could cause undesirable behavior, including
   termination of the named process.  [RT #29644]

New Features

*  None

Feature Changes

*  BIND now recognizes the TLSA resource record type, created to
   support IETF DANE (DNS-based Authentication of Named Entities)
   [RT #28989]

Bug Fixes

*  Fixes the defect introduced by change #3314 that was causing
   failures when saving stub zones to disk (resulting in excessive CPU
   usage in some cases).  [RT #29952]

*  The locking strategy around the handling of iterative queries has
   been tuned to reduce unnecessary contention in a multi-threaded
   environment.  (Note that this may not provide a measurable
   improvement over previous versions of BIND, but it corrects the
   performance impact of change 3309 / RT #27995) [RT #29239]

*  Addresses a race condition that can cause named to to crash when
   the masters list for a zone is updated via rndc reload/reconfig.
   [RT #26732]

*  Fixes a race condition in zone.c that can cause named to crash
   during the processing of rndc delzone [RT #29028]

*  Prevents a named segfault from resolver.c due to procedure
   fctx_finddone() not being thread-safe.  [RT #27995]

*  Uses hmctx, not mctx when freeing rbtdb->heaps to avoid triggering
   an assertion when flushing cache data. [RT #28571]

*  Resolves inconsistencies in locating DNSSEC keys where zone names
   contain characters that require special mappings [RT #28600]

*  A new flag -R  has been added to queryperf for running tests using
   non-recursive queries.  It also now builds correctly on MacOS
   version 10.7 (darwin)  [RT #28565]

*  Named no longer crashes if gssapi is enabled in named.conf but was
   not compiled into the binary [RT #28338]

*  SDB now handles unexpected errors from back-end database drivers
   gracefully instead of exiting on an assert. [RT #28534] 

Thank You

   Thank you to everyone who assisted us in making this release
   possible. If you would like to contribute to ISC to assist us in
   continuing to make quality open source software, please visit our
   donations page at http://www.isc.org/supportisc.

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