-
A new method of provisioning secondary servers called
"Catalog Zones" has been added. This is an implementation of
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
https://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,
http://localhost:8888/xml/v3/traffic
or
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.