BIND 9.11.0 is now available
Michael McNally
mcnally at isc.org
Tue Oct 4 22:00:09 UTC 2016
Introduction
BIND 9.11.0 is a new feature release of BIND, still under development.
This document summarizes new features and functional changes that have
been introduced on this branch. With each development release leading
up to the final BIND 9.11.0 release, this document will be updated with
additional features added and bugs fixed.
Download
The latest versions of BIND 9 software can always be found at
[1]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.
License Change
With the release of BIND 9.11.0, ISC is changing the open source
license for BIND from the ISC license to the Mozilla Public License
(MPL 2.0). This change is effective from BIND 9.11.0b1 onwards.
The MPL-2.0 license requires that if you make changes to licensed
software (e.g. BIND) and distribute them outside your organization,
that you publish those changes under that same license. It does not
require that you publish or disclose anything other than the changes
you made to our software.
This new requirement will not affect anyone who is using BIND without
redistributing it, nor anyone redistributing it without changes,
therefore this change will be without consequence for most individuals
and organizations who are using BIND.
Those unsure whether or not the license change affects their use of
BIND, or who wish to discuss how to comply with the license may contact
ISC at [2]https://www.isc.org/mission/contact/.
Security Fixes
* It was possible to trigger a assertion when rendering a message
using a specially crafted request. This flaw is disclosed in
CVE-2016-2776. [RT #43139]
* getrrsetbyname with a non absolute name could trigger an infinite
recursion bug in lwresd and named with lwres configured if when
combined with a search list entry the resulting name is too long.
This flaw is disclosed in CVE-2016-2775. [RT #42694]
New Features
* A new method of provisioning secondary servers called "Catalog
Zones" has been added. This is an implementation of
[3]draft-muks-dnsop-dns-catalog-zones/ .
A catalog zone is a regular DNS zone which contains a list of
"member zones", along with the configuration options for each of
those zones. When a server is configured to use a catalog zone, all
the zones listed in the catalog zone are added to the local server
as slave zones. When the catalog zone is updated (e.g., by adding
or removing zones, or changing configuration options for existing
zones) those changes will be put into effect. Since the catalog
zone is itself a DNS zone, this means configuration changes can be
propagated to slaves using the standard AXFR/IXFR update mechanism.
This feature should be considered experimental. It currently
supports only basic features; more advanced features such as ACLs
and TSIG keys are not yet supported. Example catalog zone
configurations can be found in the Chapter 9 of the BIND
Administrator Reference Manual.
Support for master entries with TSIG keys has been added to catalog
zones, as well as support for allow-query and allow-transfer.
* Added an isc.rndc Python module, which allows rndc commands to be
sent from Python programs.
* Added support for DynDB, a new interface for loading zone data from
an external database, developed by Red Hat for the FreeIPA project.
(Thanks in particular to Adam Tkac and Petr Spacek of Red Hat for
the contribution.)
Unlike the existing DLZ and SDB interfaces, which provide a limited
subset of database functionality within BIND -- translating DNS
queries into real-time database lookups with relatively poor
performance and with no ability to handle DNSSEC-signed data --
DynDB is able to fully implement and extend the database API used
natively by BIND.
A DynDB module could pre-load data from an external data source,
then serve it with the same performance and functionality as
conventional BIND zones, and with the ability to take advantage of
database features not available in BIND, such as multi-master
replication.
* Fetch quotas are now compiled in by default: they no longer require
BIND to be configured with --enable-fetchlimit, as was the case
when the feature was introduced in BIND 9.10.3.
These quotas limit the queries that are sent by recursive resolvers
to authoritative servers experiencing denial-of-service attacks.
They can both reduce the harm done to authoritative servers and
also avoid the resource exhaustion that can be experienced by
recursive servers when they are being used as a vehicle for such an
attack.
+ fetches-per-server limits the number of simultaneous queries
that can be sent to any single authoritative server. The
configured value is a starting point; it is automatically
adjusted downward if the server is partially or completely
non-responsive. The algorithm used to adjust the quota can be
configured via the fetch-quota-params option.
+ fetches-per-zone limits the number of simultaneous queries
that can be sent for names within a single domain. (Note:
Unlike "fetches-per-server", this value is not self-tuning.)
Statistics counters have also been added to track the number of
queries affected by these quotas.
* Added support for dnstap, a fast, flexible method for capturing and
logging DNS traffic, developed by Robert Edmonds at Farsight
Security, Inc., whose assistance is gratefully acknowledged.
To enable dnstap at compile time, the fstrm and protobuf-c
libraries must be available, and BIND must be configured with
--enable-dnstap.
A new utility dnstap-read has been added to allow dnstap data to be
presented in a human-readable format.
rndc dnstap -roll causes dnstap output files to be rolled like log
files -- the most recent output file is renamed with a .0 suffix,
the next most recent with .1, etc. (Note that this only works when
dnstap output is being written to a file, not to a UNIX domain
socket.) An optional numerical argument specifies how many backup
log files to retain; if not specified or set to 0, there is no
limit.
rndc dnstap -reopen simply closes and reopens the dnstap output
channel without renaming the output file.
For more information on dnstap, see [4]http://dnstap.info.
* New statistics counters have been added to track traffic sizes, as
specified in RSSAC002. Query and response message sizes are broken
up into ranges of histogram buckets: TCP and UDP queries of size
0-15, 16-31, ..., 272-288, and 288+, and TCP and UDP responses of
size 0-15, 16-31, ..., 4080-4095, and 4096+. These values can be
accessed via the XML and JSON statistics channels at, for example,
[5]http://localhost:8888/xml/v3/traffic or
[6]http://localhost:8888/json/v1/traffic.
Statistics for RSSAC02v3 traffic-volume, traffic-sizes and
rcode-volume reporting are now collected.
* A new DNSSEC key management utility, dnssec-keymgr, has been added.
This tool is meant to run unattended (e.g., under cron). It reads a
policy definition file (default /etc/dnssec-policy.conf) and
creates or updates DNSSEC keys as necessary to ensure that a zone's
keys match the defined policy for that zone. New keys are created
whenever necessary to ensure rollovers occur correctly. Existing
keys' timing metadata is adjusted as needed to set the correct
rollover period, prepublication interval, etc. If the configured
policy changes, keys are corrected automatically. See the
dnssec-keymgr man page for full details.
Note: dnssec-keymgr depends on Python and on the Python lex/yacc
module, PLY. The other Python-based tools, dnssec-coverage and
dnssec-checkds, have been refactored and updated as part of this
work.
dnssec-keymgr now takes a -r randomfile option.
(Many thanks to Sebastián Castro for his assistance in developing
this tool at the IETF 95 Hackathon in Buenos Aires, April 2016.)
* The serial number of a dynamically updatable zone can now be set
using rndc signing -serial number zonename. This is particularly
useful with inline-signing zones that have been reset. Setting the
serial number to a value larger than that on the slaves will
trigger an AXFR-style transfer.
* When answering recursive queries, SERVFAIL responses can now be
cached by the server for a limited time; subsequent queries for the
same query name and type will return another SERVFAIL until the
cache times out. This reduces the frequency of retries when a query
is persistently failing, which can be a burden on recursive
servers. The SERVFAIL cache timeout is controlled by servfail-ttl,
which defaults to 1 second and has an upper limit of 30.
* The new rndc nta command can now be used to set a "negative trust
anchor" (NTA), disabling DNSSEC validation for a specific domain;
this can be used when responses from a domain are known to be
failing validation due to administrative error rather than because
of a spoofing attack. NTAs are strictly temporary; by default they
expire after one hour, but can be configured to last up to one
week. The default NTA lifetime can be changed by setting the
nta-lifetime in named.conf. When added, NTAs are stored in a file
(viewname.nta) in order to persist across restarts of the named
server.
* The EDNS Client Subnet (ECS) option is now supported for
authoritative servers; if a query contains an ECS option then ACLs
containing geoip or ecs elements can match against the address
encoded in the option. This can be used to select a view for a
query, so that different answers can be provided depending on the
client network.
* The EDNS EXPIRE option has been implemented on the client side,
allowing a slave server to set the expiration timer correctly when
transferring zone data from another slave server.
* A new masterfile-style zone option controls the formatting of text
zone files: When set to full, the zone file will dumped in
single-line-per-record format.
* dig +ednsopt can now be used to set arbitrary EDNS options in DNS
requests.
* dig +ednsflags can now be used to set yet-to-be-defined EDNS flags
in DNS requests.
* dig +[no]ednsnegotiation can now be used enable / disable EDNS
version negotiation.
* dig +header-only can now be used to send queries without a question
section.
* dig +ttlunits causes dig to print TTL values with time-unit
suffixes: w, d, h, m, s for weeks, days, hours, minutes, and
seconds.
* dig +zflag can be used to set the last unassigned DNS header flag
bit. This bit is normally zero.
* dig +dscp=value can now be used to set the DSCP code point in
outgoing query packets.
* dig +mapped can now be used to determine if mapped IPv4 addresses
can be used.
* nslookup will now look up IPv6 as well as IPv4 addresses by
default. [RT #40420]
* serial-update-method can now be set to date. On update, the serial
number will be set to the current date in YYYYMMDDNN format.
* dnssec-signzone -N date also sets the serial number to YYYYMMDDNN.
* named -L filename causes named to send log messages to the
specified file by default instead of to the system log.
* The rate limiter configured by the serial-query-rate option no
longer covers NOTIFY messages; those are now separately controlled
by notify-rate and startup-notify-rate (the latter of which
controls the rate of NOTIFY messages sent when the server is first
started up or reconfigured).
* The default number of tasks and client objects available for
serving lightweight resolver queries have been increased, and are
now configurable via the new lwres-tasks and lwres-clients options
in named.conf. [RT #35857]
* Log output to files can now be buffered by specifying buffered yes;
when creating a channel.
* delv +tcp will exclusively use TCP when sending queries.
* named will now check to see whether other name server processes are
running before starting up. This is implemented in two ways: 1) by
refusing to start if the configured network interfaces all return
"address in use", and 2) by attempting to acquire a lock on a file
specified by the lock-file option or the -X command line option.
The default lock file is /var/run/named/named.lock. Specifying none
will disable the lock file check.
* rndc delzone can now be applied to zones which were configured in
named.conf; it is no longer restricted to zones which were added by
rndc addzone. (Note, however, that this does not edit named.conf;
the zone must be removed from the configuration or it will return
when named is restarted or reloaded.)
* rndc modzone can be used to reconfigure a zone, using similar
syntax to rndc addzone.
* rndc showzone displays the current configuration for a specified
zone.
* When BIND is built with the lmdb library (Lightning Memory-Mapped
Database), named will store the configuration information for zones
that are added via rndc addzone in a database, rather than in a
flat "NZF" file. This dramatically improves performance for rndc
delzone and rndc modzone: deleting or changing the contents of a
database is much faster than rewriting a text file.
On startup, if named finds an existing NZF file, it will
automatically convert it to the new NZD database format.
To view the contents of an NZD, or to convert an NZD back to an NZF
file (for example, to revert back to an earlier version of BIND
which did not support the NZD format), use the new command
named-nzd2nzf [RT #39837]
* Added server-side support for pipelined TCP queries. Clients may
continue sending queries via TCP while previous queries are
processed in parallel. Responses are sent when they are ready, not
necessarily in the order in which the queries were received.
To revert to the former behavior for a particular client address or
range of addresses, specify the address prefix in the
"keep-response-order" option. To revert to the former behavior for
all clients, use "keep-response-order { any; };".
* The new mdig command is a version of dig that sends multiple
pipelined queries and then waits for responses, instead of sending
one query and waiting the response before sending the next. [RT
#38261]
* To enable better monitoring and troubleshooting of RFC 5011 trust
anchor management, the new rndc managed-keys can be used to check
status of trust anchors or to force keys to be refreshed. Also, the
managed-keys data file now has easier-to-read comments. [RT #38458]
* An --enable-querytrace configure switch is now available to enable
very verbose query trace logging. This option can only be set at
compile time. This option has a negative performance impact and
should be used only for debugging. [RT #37520]
* A new tcp-only option can be specified in server statements to
force named to connect to the specified server via TCP. [RT #37800]
* The nxdomain-redirect option specifies a DNS namespace to use for
NXDOMAIN redirection. When a recursive lookup returns NXDOMAIN, a
second lookup is initiated with the specified name appended to the
query name. This allows NXDOMAIN redirection data to be supplied by
multiple zones configured on the server, or by recursive queries to
other servers. (The older method, using a single type redirect
zone, has better average performance but is less flexible.) [RT
#37989]
* The following types have been implemented: CSYNC, NINFO, RKEY,
SINK, TA, TALINK.
* A new message-compression option can be used to specify whether or
not to use name compression when answering queries. Setting this to
no results in larger responses, but reduces CPU consumption and may
improve throughput. The default is yes.
* A read-only option is now available in the controls statement to
grant non-destructive control channel access. In such cases, a
restricted set of rndc commands are allowed, which can report
information from named, but cannot reconfigure or stop the server.
By default, the control channel access is not restricted to these
read-only operations. [RT #40498]
* When loading a signed zone, named will now check whether an RRSIG's
inception time is in the future, and if so, it will regenerate the
RRSIG immediately. This helps when a system's clock needs to be
reset backwards.
* The new minimal-any option reduces the size of answers to UDP
queries for type ANY by implementing one of the strategies in
"draft-ietf-dnsop-refuse-any": returning a single
arbitrarily-selected RRset that matches the query name rather than
returning all of the matching RRsets. Thanks to Tony Finch for the
contribution. [RT #41615]
* named now provides feedback to the owners of zones which have trust
anchors configured (trusted-keys, managed-keys, dnssec-validation
auto; and dnssec-lookaside auto;) by sending a daily query which
encodes the keyids of the configured trust anchors for the zone.
This is controlled by trust-anchor-telemetry and defaults to yes.
Feature Changes
* The logging format used for querylog has been altered. It now
includes an additional field indicating the address in memory of
the client object processing the query.
The ISC DNSSEC Lookaside Validation (DLV) service is scheduled to
be disabled in 2017. A warning is now logged when named is
configured to use this service, either explicitly or via
dnssec-lookaside auto;. [RT #42207]
* The timers returned by the statistics channel (indicating current
time, server boot time, and most recent reconfiguration time) are
now reported with millisecond accuracy. [RT #40082]
* Updated the compiled-in addresses for H.ROOT-SERVERS.NET and
L.ROOT-SERVERS.NET.
* ACLs containing geoip asnum elements were not correctly matched
unless the full organization name was specified in the ACL (as in
geoip asnum "AS1234 Example, Inc.";). They can now match against
the AS number alone (as in geoip asnum "AS1234";).
* When using native PKCS#11 cryptography (i.e., configure
--enable-native-pkcs11) HSM PINs of up to 256 characters can now be
used.
* NXDOMAIN responses to queries of type DS are now cached separately
from those for other types. This helps when using "grafted" zones
of type forward, for which the parent zone does not contain a
delegation, such as local top-level domains. Previously a query of
type DS for such a zone could cause the zone apex to be cached as
NXDOMAIN, blocking all subsequent queries. (Note: This change is
only helpful when DNSSEC validation is not enabled. "Grafted" zones
without a delegation in the parent are not a recommended
configuration.)
* Update forwarding performance has been improved by allowing a
single TCP connection to be shared between multiple updates.
* By default, nsupdate will now check the correctness of hostnames
when adding records of type A, AAAA, MX, SOA, NS, SRV or PTR. This
behavior can be disabled with check-names no.
* Added support for OPENPGPKEY type.
* The names of the files used to store managed keys and added zones
for each view are no longer based on the SHA256 hash of the view
name, except when this is necessary because the view name contains
characters that would be incompatible with use as a file name. For
views whose names do not contain forward slashes ('/'), backslashes
('\'), or capital letters - which could potentially cause namespace
collision problems on case-insensitive filesystems - files will now
be named after the view (for example, internal.mkeys or
external.nzf). However, to ensure consistent behavior when
upgrading, if a file using the old name format is found to exist,
it will continue to be used.
* "rndc" can now return text output of arbitrary size to the caller.
(Prior to this, certain commands such as "rndc tsig-list" and "rndc
zonestatus" could return truncated output.)
* Errors reported when running rndc addzone (e.g., when a zone file
cannot be loaded) have been clarified to make it easier to diagnose
problems.
* When encountering an authoritative name server whose name is an
alias pointing to another name, the resolver treats this as an
error and skips to the next server. Previously this happened
silently; now the error will be logged to the newly-created "cname"
log category.
* If named is not configured to validate answers, then allow fallback
to plain DNS on timeout even when we know the server supports EDNS.
This will allow the server to potentially resolve signed queries
when TCP is being blocked.
* Large inline-signing changes should be less disruptive. Signature
generation is now done incrementally; the number of signatures to
be generated in each quantum is controlled by
"sig-signing-signatures number;". [RT #37927]
* The experimental SIT option (code point 65001) of BIND 9.10.0
through BIND 9.10.2 has been replaced with the COOKIE option (code
point 10). It is no longer experimental, and is sent by default, by
both named and dig.
The SIT-related named.conf options have been marked as obsolete,
and are otherwise ignored.
* When dig receives a truncated (TC=1) response or a BADCOOKIE
response code from a server, it will automatically retry the query
using the server COOKIE that was returned by the server in its
initial response. [RT #39047]
* Retrieving the local port range from net.ipv4.ip_local_port_range
on Linux is now supported.
* A new nsip-wait-recurse directive has been added to RPZ, specifying
whether to look up unknown name server IP addresses and wait for a
response before applying RPZ-NSIP rules. The default is yes. If set
to no, named will only apply RPZ-NSIP rules to servers whose
addresses are already cached. The addresses will be looked up in
the background so the rule can be applied on subsequent queries.
This improves performance when the cache is cold, at the cost of
temporary imprecision in applying policy directives. [RT #35009]
* Within the response-policy option, it is now possible to configure
RPZ rewrite logging on a per-zone basis using the log clause.
* The default preferred glue is now the address type of the transport
the query was received over.
* On machines with 2 or more processors (CPU), the default value for
the number of UDP listeners has been changed to the number of
detected processors minus one.
* Zone transfers now use smaller message sizes to improve message
compression. This results in reduced network usage.
* Added support for the AVC resource record type (Application
Visibility and Control).
Changed rndc reconfig behavior so that newly added zones are loaded
asynchronously and the loading does not block the server.
* minimal-responses now takes two new arguments: no-auth suppresses
populating the authority section but not the additional section;
no-auth-recursive does the same but only when answering recursive
queries.
* At server startup time, the queues for processing notify and zone
refresh queries are now processed in LIFO rather than FIFO order,
to speed up loading of newly added zones. [RT #42825]
* When answering queries of type MX or SRV, TLSA records for the
target name are now included in the additional section to speed up
DANE processing. [RT #42894]
* named can now use the TCP Fast Open mechanism on the server side,
if supported by the local operating system. [RT #42866]
Bug Fixes
* Fixed a crash when calling rndc stats on some Windows builds: some
Visual Studio compilers generate code that crashes when the "%z"
printf() format specifier is used. [RT #42380]
* Windows installs were failing due to triggering UAC without the
installation binary being signed.
* A change in the internal binary representation of the RBT database
node structure enabled a race condition to occur (especially when
BIND was built with certain compilers or optimizer settings),
leading to inconsistent database state which caused random
assertion failures. [RT #42380]
End of Life
The end of life for BIND 9.11 is yet to be determined but will not be
before BIND 9.13.0 has been released for 6 months.
[7]https://www.isc.org/downloads/software-support-policy/
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
[8]http://www.isc.org/donate/.
References
1. http://www.isc.org/downloads/
2. https://www.isc.org/mission/contact/
3. https://datatracker.ietf.org/doc/draft-muks-dnsop-dns-catalog-zones/
4. http://dnstap.info/
5. http://localhost:8888/xml/v3/traffic
6. http://localhost:8888/json/v1/traffic
7. https://www.isc.org/downloads/software-support-policy/
8. http://www.isc.org/donate/
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