BIND 9.12.0 is now available
mcnally at isc.org
Tue Jan 23 22:59:45 UTC 2018
BIND 9.12.0 is a new feature release of BIND. This document summarizes
new features and functional changes that have been introduced on this
branch, as well as features that have been deprecated or removed.
The latest versions of BIND 9 software can always be found at
http://www.isc.org/downloads/. There you will find additional
information about each release, source code, and pre-compiled versions
for Microsoft Windows operating systems.
* Many aspects of named have been modified to improve query
performance, and in particular, performance for delegation-heavy
+ The additional cache ("acache") was found not to significantly
improve performance and has been removed. As a result, the
acache-enable and acache-cleaning-interval options no longer
have any effect. For backwards compatibility, BIND will accept
their presence in a configuration file, but will log a
+ In place of the acache, named can now use a glue cache to
speed up retrieval of glue records when sending delegation
responses. Unlike acache, this feature is on by default; use
glue-cache no; to disable it.
+ minimal-responses is now set to no-auth-recursive by default.
+ The additional-from-cache and additional-from-auth options no
longer have any effect. named will log a warning if they are
+ Several functions have been refactored to improve performance,
including name compression, owner name case restoration,
hashing, and buffers.
+ When built with default configure options, named no longer
fills memory with tag values when allocating or freeing it.
This improves performance, but makes it more difficult to
debug certain memory-related errors. The default is reversed
if building with developer options. named -M fill or named -M
nofill will set the behavior accordingly regardless of build
* Several areas of code have been refactored for improved
readability, maintainability, and testability:
+ The named query logic implemented in query_find() has been
split into smaller functions with a context structure to
maintain state between them, and extensive comments have been
added. [RT #43929]
+ Similarly the iterative query logic implemented in
resquery_response() function has been split into smaller
functions and comments added. [RT #45362]
* Code implementing name server query processing has been moved from
named to an external library, libns. This will make it easier to
write unit tests for the code, or to link it into new tools. [RT
* named can now synthesize negative responses (NXDOMAIN, NODATA, or
wildcard answers) from cached DNSSEC-verified records that were
returned in negative or wildcard responses from authoritative
This will reduce query loads on authoritative servers for signed
domains: when existing cached records can be used by the resolver
to determine that a name does not exist in the authoritative
domain, no query needs to be sent. Reducing the number of iterative
queries should also improve resolver performance.
This behavior is controlled by the new named.conf option
synth-from-dnssec. It is enabled by default.
Note: this currently only works for zones signed using NSEC.
Support for zones signed using NSEC3 (without opt-out) is planned
for the future.
Thanks to APNIC for sponsoring this work.
* When acting as a recursive resolver, named can now continue
returning answers whose TTLs have expired when the authoritative
server is under attack and unable to respond. This is controlled by
the stale-answer-enable, stale-answer-ttl and max-stale-ttl
options. [RT #44790]
* The DNS Response Policy Service (DNSRPS) API, a mechanism to allow
named to use an external response policy provider, is now
supported. (One example of such a provider is "FastRPZ" from
Farsight Security, Inc.) This allows the same types of policy
filtering as standard RPZ, but can reduce the workload for named,
particularly when using large and frequently-updated policy zones.
It also enables named to share response policy providers with other
DNS implementations such as Unbound.
This feature is available if BIND is built with configure
--enable-dnsrps, if a DNSRPS provider is installed, and if
dnsrps-enable is set to "yes" in named.conf. Standard built-in RPZ
is used otherwise.
Thanks to Farsight Security for the contribution. [RT #43376]
* Setting max-journal-size to default limits journal sizes to twice
the size of the zone contents. This can be overridden by setting
max-journal-size to unlimited or to an explicit value up to 2G.
Thanks to Tony Finch for the contribution. [RT #38324]
* dnstap logfiles can now be configured to automatically roll when
they reach a specified size. If dnstap-output is configured with
mode file, then it can take optional size and versions key-value
arguments to set the logfile rolling parameters. (These have the
same semantics as the corresponding options in a logging channel
statement.) [RT #44502]
* Logging channels and dnstap-output files can now be configured with
a suffix option, set to either increment or timestamp, indicating
whether log files should be given incrementing suffixes when they
roll over (e.g., logfile.0, .1, .2, etc) or suffixes indicating the
time of the roll. The default is increment. [RT #42838]
* The print-time option in the logging configuration can now take
arguments local, iso8601 or iso8601-utc to indicate the format in
which the date and time should be logged. For backward
compatibility, yes is a synonym for local. [RT #42585]
* The new dnssec-cds command generates a new DS set to place in a
parent zone, based on the contents of a child zone's validated CDS
or CDNSKEY records. It can produce a dsset file suitable for input
to dnssec-signzone, or a series of nsupdate commands to update the
parent zone via dynamic DNS. Thanks to Tony Finch for the
contribution. [RT #46090]
* nsupdate and rndc now accept command line options -4 and -6 which
force using only IPv4 or only IPv6, respectively. [RT #45632]
* nsec3hash -r ("rdata order") takes arguments in the same order as
they appear in NSEC3 or NSEC3PARAM records. This makes it easier to
generate an NSEC3 hash using values cut and pasted from an existing
record. Thanks to Tony Finch for the contribution. [RT #45183]
* The new-zones-directory option allows named to store configuration
parameters for zones added via rndc addzone in a location other
than the working directory. Thanks to Petr Mensík of Red Hat for
the contribution. [RT #44853]
* The dnstap-read -x option prints a hex dump of the wire format DNS
message encapsulated in each dnstap log entry. [RT #44816]
* The host -A option returns most records for a name, but omits types
RRSIG, NSEC and NSEC3.
* dig +ednsopt now accepts the names for EDNS options in addition to
numeric values. For example, an EDNS Client-Subnet option could be
sent using dig +ednsopt=ecs:.... Thanks to John Worley of Secure64
for the contribution. [RT #44461]
* Added support for the EDNS TCP Keepalive option (RFC 7828); this
allows negotiation of longer-lived TCP sessions to reduce the
overhead of setting up TCP for individual queries. [RT #42126]
* Added support for the EDNS Padding option (RFC 7830), which
obfuscates packet size analysis when DNS queries are sent over an
encrypted channel. [RT #42094]
* rndc commands which refer to zone names can now reference a zone of
type redirect by using the special zone name "-redirect".
(Previously this was not possible because redirect zones always
have the name ".", which can be ambiguous.)
In the event you need to manipulate a zone actually called
"-redirect", use a trailing dot: "-redirect."
Note: This change does not apply to the rndc addzone or rndc
* named-checkconf -l lists the zones found in named.conf. [RT #43154]
* Query logging now includes the ECS option, if one was present in
the query, in the format "[ECS address/source/scope]".
* By default, BIND now uses the random number generation functions in
the cryptographic library (i.e., OpenSSL or a PKCS#11 provider) as
a source of high-quality randomness rather than /dev/random. This
is suitable for virtual machine environments, which may have
limited entropy pools and lack hardware random number generators.
This can be overridden by specifying another entropy source via the
random-device option in named.conf, or via the -r command line
option. However, for functions requiring full cryptographic
strength, such as DNSSEC key generation, this cannot be overridden.
In particular, the -r command line option no longer has any effect
This can be disabled by building with configure
--disable-crypto-rand, in which case /dev/random will be the
default entropy source. [RT #31459] [RT #46047]
* rndc managed-keys destroy shuts down all RFC 5011 DNSSEC trust
anchor maintenance, and deletes any existing managed keys database.
If immediately followed by rndc reconfig, this will reinitialize
key maintenance just as if the server was being started for the
This is intended for testing purposes, but can be used -- with
extreme caution -- as a brute-force repair for unrecoverable
problems with a managed keys database, to jumpstart the key
acquisition process if bind.keys is updated, etc. [RT #32456]
* dnssec-signzone -S can now add or remove synchronization records
(CDS and CDNSKEY) based on key metadata set by the -Psync and
-Dsync options to dnssec-keygen, dnssec-settime, etc. [RT #46149]
* dnssec-checkds -s specifies a file from which to read a DS set
rather than querying the parent zone. This can be used to check
zone correctness prior to publication. Thanks to Niall O'Reilly [RT
* As noted above, the acache-enable, acache-cleaning-interval,
additional-from-cache and additional-from-auth options are no
longer effective and named will log a warning if they are set.
* The ISC DNSSEC Lookaside Validation (DLV) service has been shut
down; all DLV records in the dlv.isc.org zone have been removed.
References to the service have been removed from BIND
documentation. Lookaside validation is no longer used by default by
delv. The DLV key has been removed from bind.keys. Setting
dnssec-lookaside to auto or to use dlv.isc.org as a trust anchor
results in a warning being issued.
* The lightweight resolver daemon and library (lwresd and liblwres)
have been removed. [RT #45186]
* dig +sigchase and related options +trusted-keys and +topdown have
been removed. delv is now the recommended command for looking up
records with DNSSEC validation. [RT #42793]
* The use of dnssec-keygen to generate HMAC keys for TSIG
authentication has been deprecated in favor of tsig-keygen. If the
algorithms HMAC-MD5, HMAC-SHA1, HMAC-SHA224, HMAC-SHA256,
HMAC-SHA384, or HMAC-SHA512 are specified, dnssec-keygen will print
a warning message. These algorithms will be removed from
dnssec-keygen entirely in a future release. [RT #42272]
* The use of HMAC-MD5 for RNDC keys is no longer recommended. The
default algorithm generated by rndc-confgen is now HMAC-SHA256. [RT
* The isc-hmac-fixup command, which was created to address an
interoperability problem in TSIG keys between early versions of
BIND and other DNS implementations, is now obsolete and has been
removed. [RT #46411]
* Windows XP and Windows 2003 are no longer supported platforms for
BIND; "XP" binaries are no longer available for download from ISC.
* BIND can now use the Ed25519 and Ed448 Edwards Curve DNSSEC signing
algorithms described in RFC 8080. Note, however, that these
algorithms must be supported in OpenSSL; currently they are only
available in the development branch of OpenSSL at
https://github.com/openssl/openssl. [RT #44696]
* When parsing DNS messages, EDNS KEY TAG options are checked for
correctness. When printing messages (for example, in dig), EDNS KEY
TAG options are printed in readable format.
* named will no longer start or accept reconfiguration if the working
directory (specified by the directory option) or the managed-keys
directory (specified by managed-keys-directory are not writable by
the effective user ID. [RT #46077]
* Initializing keys specified in a managed-keys statement or by
dnssec-validation auto; are now tagged as "initializing", until
they have been updated by a key refresh query. If key maintenance
fails to initialize, this will be visible when running rndc
secroots. [RT #46267]
* Previously, update-policy local; accepted updates from any source
so long as they were signed by the locally-generated session key.
This has been further restricted; updates are now only accepted
from locally configured addresses. [RT #45492]
* dnssec-keygen no longer has default algorithm settings. It is
necessary to explicitly specify the algorithm on the command line
with the -a option when generating keys. This may cause errors with
existing signing scripts if they rely on current defaults. The
intent is to reduce the long-term cost of transitioning to newer
algorithms in the event of RSASHA1 being deprecated. [RT #44755]
* The Response Policy Zone (RPZ) implementation has been
substantially refactored: updates to the RPZ summary database are
no longer directly performed by the zone database but by a separate
function that is called when a policy zone is updated. This
improves both performance and reliability when policy zones receive
frequent updates. Summary database updates can be rate-limited by
using the min-update-interval option in a response-policy
statement. [RT #43449]
* dnstap now stores both the local and remote addresses for all
messages, instead of only the remote address. The default output
format for dnstap-read has been updated to include these addresses,
with the initiating address first and the responding address
second, separated by "->" or "<-" to indicate in which direction
the message was sent. [RT #43595]
* Expanded and improved the YAML output from dnstap-read -y: it now
includes packet size and a detailed breakdown of message contents.
[RT #43622] [RT #43642]
* Threads in named are now set to human-readable names to assist
debugging on operating systems that support that. Threads will have
names such as "isc-timer", "isc-sockmgr", "isc-worker0001", and so
on. This will affect the reporting of subsidiary thread names in ps
and top, but not the main thread. [RT #43234]
* If an ACL is specified with an address prefix in which the prefix
length is longer than the address portion (for example,
192.0.2.1/8), it will now be treated as a fatal error during
configuration. [RT #43367]
* dig now warns about .local queries which are reserved for Multicast
DNS. [RT #44783]
* The view associated with the query is now logged unless it it is
"_default/IN" or "_dnsclient/IN" when logging DNSSEC validator
* When named was reconfigured, failure of some zones to load
correctly could leave the system in an inconsistent state; while
generally harmless, this could lead to a crash later when using
rndc addzone. Reconfiguration changes are now fully rolled back in
the event of failure. [RT #45841]
* Multiple cookie-secret clauses are now supported. The first
cookie-secret in named.conf is used to generate new server cookies.
Any others are used to accept old server cookies or those generated
by other servers using the matching cookie-secret.
* A new statistics counter has been added to track prefetch queries.
* A new statistics counter has been added to track priming queries.
* The dnssec-signzone -x flag and the dnssec-dnskey-kskonly option in
named.conf, which suppress the use of the ZSK when signing DNSKEY
records, now also apply to CDNSKEY and CDS records. Thanks to Tony
Finch for the contribution. [RT #45689]
* Trust anchor telemetry messages, as specified by RFC 8145, are now
logged to the trust-anchor-telemetry logging category.
* The filter-aaaa-on-v4 and filter-aaaa-on-v6 options are no longer
conditionally compiled in named. [RT #46340]
BIND is open source software licenced under the terms of the Mozilla
Public License, version 2.0 (see the LICENSE file for the full text).
The license requires that if you make changes to BIND and distribute
them outside your organization, those changes must be published under
the same license. It does not require that you publish or disclose
anything other than the changes you have made to our software. This
requirement does not affect anyone who is using BIND, with or without
modifications, without redistributing it, nor anyone redistributing
BIND without changes.
Those wishing to discuss license compliance may contact ISC at
End of Life
The end-of-life date for BIND 9.12 has not yet been determined.
However, it is not intended to be an Extended Support Version (ESV)
branch; accordingly, support will end after the next stable branch
(9.14) becomes available. Those needing a longer-lived branch are
encouraged to use the current ESV, BIND 9.11, which will be supported
until December 2021. See
https://www.isc.org/downloads/software-support-policy/ for details of
ISC's software support policy.
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
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