.. Copyright (C) Internet Systems Consortium, Inc. ("ISC") .. .. SPDX-License-Identifier: MPL-2.0 .. .. This Source Code Form is subject to the terms of the Mozilla Public .. License, v. 2.0. If a copy of the MPL was not distributed with this .. file, you can obtain one at https://mozilla.org/MPL/2.0/. .. .. See the COPYRIGHT file distributed with this work for additional .. information regarding copyright ownership. Notes for BIND 9.18.0 --------------------- .. note:: This section only lists changes since BIND 9.16.25, the most recent release on the previous stable branch of BIND before the publication of BIND 9.18.0. Known Issues ~~~~~~~~~~~~ - ``rndc`` has been updated to use the new BIND network manager API. As the network manager currently has no support for UNIX-domain sockets, those cannot now be used with ``rndc``. This will be addressed in a future release, either by restoring UNIX-domain socket support or by formally declaring them to be obsolete in the control channel. :gl:`#1759` - See :ref:`above ` for a list of all known issues affecting this BIND 9 branch. New Features ~~~~~~~~~~~~ - ``named`` now supports securing DNS traffic using Transport Layer Security (TLS). TLS is used by both DNS over TLS (DoT) and DNS over HTTPS (DoH). ``named`` can use either a certificate provided by the user or an ephemeral certificate generated automatically upon startup. The :any:`tls` block allows fine-grained control over TLS parameters. :gl:`#1840` :gl:`#2795` :gl:`#2796` For debugging purposes, ``named`` logs TLS pre-master secrets when the ``SSLKEYLOGFILE`` environment variable is set. This enables troubleshooting of issues with encrypted traffic. :gl:`#2723` - Support for DNS over TLS (DoT) has been added to ``named``. Network interfaces for DoT are configured using the existing :ref:`listen-on ` directive, while TLS parameters are configured using the new :any:`tls` block. :gl:`#1840` ``named`` supports :rfc:`zone transfers over TLS <9103>` (XFR-over-TLS, XoT) for both incoming and outgoing zone transfers. Incoming zone transfers over TLS are enabled by adding the :any:`tls` keyword, followed by either the name of a previously configured :any:`tls` block or the string ``ephemeral``, to the addresses included in :any:`primaries` lists. :gl:`#2392` Similarly, the :any:`allow-transfer` option was extended to accept additional ``port`` and ``transport`` parameters, to further restrict outgoing zone transfers to a particular port and/or DNS transport protocol. :gl:`#2776` Note that zone transfers over TLS (XoT) require the ``dot`` Application-Layer Protocol Negotiation (ALPN) token to be selected in the TLS handshake, as required by :rfc:`9103` section 7.1. This might cause issues with non-compliant XoT servers. :gl:`#2794` The ``dig`` tool is now able to send DoT queries (``+tls`` option). :gl:`#1840` There is currently no support for forwarding DNS queries via DoT. - Support for DNS over HTTPS (DoH) has been added to ``named``. Both TLS-encrypted and unencrypted connections are supported (the latter may be used to offload encryption to other software). Network interfaces for DoH are configured using the existing :ref:`listen-on ` directive, while TLS parameters are configured using the new :any:`tls` block and HTTP parameters are configured using the new :any:`http` block. :gl:`#1144` :gl:`#2472` Server-side quotas on both the number of concurrent DoH connections and the number of active HTTP/2 streams per connection can be configured using the global :any:`http-listener-clients` and :any:`http-streams-per-connection` options, or the :any:`listener-clients` and :any:`streams-per-connection` parameters in an :any:`http block `. :gl:`#2809` The ``dig`` tool is now able to send DoH queries (``+https`` option). :gl:`#1641` There is currently no support for forwarding DNS queries via DoH. DoH support can be disabled at compile time using a new build-time option, ``--disable-doh``. This allows BIND 9 to be built without the `libnghttp2`_ library. :gl:`#2478` - A new logging category, ``rpz-passthru``, was added, which allows RPZ passthru actions to be logged into a separate channel. :gl:`#54` - A new option, ``nsdname-wait-recurse``, has been added to the :any:`response-policy` clause in the configuration file. When set to ``no``, RPZ NSDNAME rules are only applied if the authoritative nameservers for the query name have been looked up and are present in the cache. If this information is not present, the RPZ NSDNAME rules are ignored, but the information is looked up in the background and applied to subsequent queries. The default is ``yes``, meaning that RPZ NSDNAME rules should always be applied, even if the information needs to be looked up first. :gl:`#1138` - Support for HTTPS and SVCB record types now also includes ADDITIONAL section processing for these record types. :gl:`#1132` - New configuration options, :any:`tcp-receive-buffer`, :any:`tcp-send-buffer`, :any:`udp-receive-buffer`, and :any:`udp-send-buffer`, have been added. These options allow the operator to fine-tune the receiving and sending buffers in the operating system. On busy servers, increasing the size of the receive buffers can prevent the server from dropping packets during short traffic spikes, and decreasing it can prevent the server from becoming clogged with queries that are too old and have already timed out. :gl:`#2313` - New finer-grained :any:`update-policy` rule types, ``krb5-subdomain-self-rhs`` and ``ms-subdomain-self-rhs``, were added. These rule types restrict updates to SRV and PTR records so that their content can only match the machine name embedded in the Kerberos principal making the change. :gl:`#481` - Per-type record count limits can now be specified in :any:`update-policy` statements, to limit the number of records of a particular type that can be added to a domain name via dynamic update. :gl:`#1657` - Support for OpenSSL 3.0 APIs was added. :gl:`#2843` :gl:`#3057` - Extended DNS Error Code 18 - Prohibited (see :rfc:`8914` section 4.19) is now set if query access is denied to the specific client. :gl:`#1836` - ``ipv4only.arpa`` is now served when DNS64 is configured. :gl:`#385` - ``dig`` can now report the DNS64 prefixes in use (``+dns64prefix``). This is useful when the host on which ``dig`` is run is behind an IPv6-only link, using DNS64/NAT64 or 464XLAT for IPv4aaS (IPv4 as a Service). :gl:`#1154` - ``dig`` output now includes the transport protocol used (UDP, TCP, TLS, HTTPS). :gl:`#1144` :gl:`#1816` - ``dig +qid=`` allows the user to specify a particular query ID for testing purposes. :gl:`#1851` .. _libnghttp2: https://nghttp2.org/ Removed Features ~~~~~~~~~~~~~~~~ - Support for the ``map`` zone file format (``masterfile-format map;``) has been removed. Users relying on the ``map`` format are advised to convert their zones to the ``raw`` format with ``named-compilezone`` and change the configuration appropriately prior to upgrading BIND 9. :gl:`#2882` - Old-style Dynamically Loadable Zones (DLZ) drivers that had to be enabled in ``named`` at build time have been removed. New-style DLZ modules should be used as a replacement. :gl:`#2814` - Support for compiling and running BIND 9 natively on Windows has been completely removed. The last stable release branch that has working Windows support is BIND 9.16. :gl:`#2690` - Native PKCS#11 support has been removed. :gl:`#2691` When built against OpenSSL 1.x, BIND 9 now :ref:`uses engine_pkcs11 for PKCS#11 `. engine_pkcs11 is an OpenSSL engine which is part of the `OpenSC`_ project. As support for so-called "engines" was deprecated in OpenSSL 3.x, compiling BIND 9 against an OpenSSL 3.x build which does not retain support for deprecated APIs makes it impossible to use PKCS#11 in BIND 9. A replacement for engine_pkcs11 which employs the new "provider" approach introduced in OpenSSL 3.x is in the making. :gl:`#2843` - The utilities ``dnssec-checkds``, ``dnssec-coverage``, and ``dnssec-keymgr`` have been removed from the BIND distribution, as well as the ``isc`` Python package. DNSSEC features formerly provided by these utilities are now integrated into ``named``. See the :any:`dnssec-policy` configuration option for more details. An archival version of the Python utilities has been moved to the repository https://gitlab.isc.org/isc-projects/dnssec-keymgr/. Please note these tools are no longer supported by ISC. - Since the old socket manager API has been removed, "socketmgr" statistics are no longer reported by the :any:`statistics-channels`. :gl:`#2926` - The :any:`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` - A number of non-working configuration options that had been marked as obsolete in previous releases have now been removed completely. Using any of the following options is now considered a configuration failure: ``acache-cleaning-interval``, ``acache-enable``, ``additional-from-auth``, ``additional-from-cache``, ``allow-v6-synthesis``, ``cleaning-interval``, ``dnssec-enable``, ``dnssec-lookaside``, ``filter-aaaa``, ``filter-aaaa-on-v4``, ``filter-aaaa-on-v6``, ``geoip-use-ecs``, ``lwres``, ``max-acache-size``, ``nosit-udp-size``, ``queryport-pool-ports``, ``queryport-pool-updateinterval``, ``request-sit``, ``sit-secret``, ``support-ixfr``, ``use-queryport-pool``, ``use-ixfr``. :gl:`#1086` - The ``dig`` option ``+unexpected`` has been removed. :gl:`#2140` - IPv6 sockets are now explicitly restricted to sending and receiving IPv6 packets only. As this breaks the ``+mapped`` option for ``dig``, the option has been removed. :gl:`#3093` - Disable and disallow static linking of BIND 9 binaries and libraries as BIND 9 modules require ``dlopen()`` support and static linking also prevents using security features like read-only relocations (RELRO) or address space layout randomization (ASLR) which are important for programs that interact with the network and process arbitrary user input. :gl:`#1933` - The ``--with-gperftools-profiler`` ``configure`` option was removed. To use the gperftools profiler, the ``HAVE_GPERFTOOLS_PROFILER`` macro now needs to be manually set in ``CFLAGS`` and ``-lprofiler`` needs to be present in ``LDFLAGS``. :gl:`!4045` .. _OpenSC: https://github.com/OpenSC/libp11 Feature Changes ~~~~~~~~~~~~~~~ - Aggressive Use of DNSSEC-Validated Cache (:any:`synth-from-dnssec`, see :rfc:`8198`) is now enabled by default again, after having been disabled in BIND 9.14.8. The implementation of this feature was reworked to achieve better efficiency and tuned to ignore certain types of broken NSEC records. Negative answer synthesis is currently only supported for zones using NSEC. :gl:`#1265` - The default NSEC3 parameters for :any:`dnssec-policy` were updated to no extra SHA-1 iterations and no salt (``NSEC3PARAM 1 0 0 -``). This change is in line with the `latest NSEC3 recommendations`_. :gl:`#2956` - The default for :any:`dnssec-dnskey-kskonly` was changed to ``yes``. This means that DNSKEY, CDNSKEY, and CDS RRsets are now only signed with the KSK by default. The additional signatures prepared using the ZSK when the option is set to ``no`` add to the DNS response payload without offering added value. :gl:`#1316` - ``dnssec-cds`` now only generates SHA-2 DS records by default and avoids copying deprecated SHA-1 records from a child zone to its delegation in the parent. If the child zone does not publish SHA-2 CDS records, ``dnssec-cds`` will generate them from the CDNSKEY records. The ``-a algorithm`` option now affects the process of generating DS digest records from both CDS and CDNSKEY records. Thanks to Tony Finch. :gl:`#2871` - Previously, ``named`` accepted FORMERR responses both with and without an OPT record, as an indication that a given server did not support EDNS. To implement full compliance with :rfc:`6891`, only FORMERR responses without an OPT record are now accepted. This intentionally breaks communication with servers that do not support EDNS and that incorrectly echo back the query message with the RCODE field set to FORMERR and the QR bit set to 1. :gl:`#2249` - The question section is now checked when processing AXFR, IXFR, and SOA replies while transferring a zone in. :gl:`#1683` - DNS Flag Day 2020: the EDNS buffer size probing code, which made the resolver adjust the EDNS buffer size used for outgoing queries based on the successful query responses and timeouts observed, was removed. The resolver now always uses the EDNS buffer size set in :any:`edns-udp-size` for all outgoing queries. :gl:`#2183` - Keeping stale answers in cache (:any:`stale-cache-enable`) has been disabled by default. :gl:`#1712` - Overall memory use by ``named`` has been optimized and significantly reduced, especially for resolver workloads. :gl:`#2398` :gl:`#3048` - Memory allocation is now based on the memory allocation API provided by the `jemalloc`_ library, on platforms where it is available. Use of this library is now recommended when building BIND 9; although it is optional, it is enabled by default. :gl:`#2433` - Internal data structures maintained for each cache database are now grown incrementally when they need to be expanded. This helps maintain a steady response rate on a loaded resolver while these internal data structures are resized. :gl:`#2941` - The interface handling code has been refactored to use fewer resources, which should lead to less memory fragmentation and better startup performance. :gl:`#2433` - When reporting zone types in the statistics channel, the terms :any:`primary ` and :any:`secondary ` are now used instead of ``master`` and ``slave``, respectively. :gl:`#1944` - The ``rndc nta -dump`` and ``rndc secroots`` commands now both include :any:`validate-except` entries when listing negative trust anchors. These are indicated by the keyword ``permanent`` in place of the expiry date. :gl:`#1532` - The output of ``rndc serve-stale status`` has been clarified. It now explicitly reports whether retention of stale data in the cache is enabled (:any:`stale-cache-enable`), and whether returning such data in responses is enabled (:any:`stale-answer-enable`). :gl:`#2742` - Previously, using ``dig +bufsize=0`` had the side effect of disabling EDNS, and there was no way to test the remote server's behavior when it had received a packet with EDNS0 buffer size set to 0. This is no longer the case; ``dig +bufsize=0`` now sends a DNS message with EDNS version 0 and buffer size set to 0. To disable EDNS, use ``dig +noedns``. :gl:`#2054` - BIND 9 binaries which are neither daemons nor administrative programs were moved to ``$bindir``. Only ``ddns-confgen``, ``named``, ``rndc``, ``rndc-confgen``, and ``tsig-confgen`` were left in ``$sbindir``. :gl:`#1724` - The BIND 9 build system has been changed to use a typical autoconf+automake+libtool stack. This should not make any difference for people building BIND 9 from release tarballs, but when building BIND 9 from the Git repository, ``autoreconf -fi`` needs to be run first. Extra attention is also needed when using non-standard ``configure`` options. :gl:`#4` .. _latest NSEC3 recommendations: https://datatracker.ietf.org/doc/html/draft-ietf-dnsop-nsec3-guidance-02 .. _jemalloc: http://jemalloc.net/ Bug Fixes ~~~~~~~~~ - Log files using ``timestamp``-style suffixes were not always correctly removed when the number of files exceeded the limit set by ``versions``. This has been fixed. :gl:`#828`