These options were ancient or made obsolete a long time ago, it is
safe to remove them.
Also stop printing ancient options, they should be treated the same as
unknown options.
Removed options: lwres, geoip-use-ecs, sit-secret, use-ixfr,
acache-cleaning-interval, acache-enable, additional-from-auth,
additional-from-cache, allow-v6-synthesis, dnssec-enable,
max-acache-size, nosit-udp-size, queryport-pool-ports,
queryport-pool-updateinterval, request-sit, use-queryport-pool, and
support-ixfr.
The DNS Flag Day 2020 reduced all the EDNS buffer sizes to 1232. In
this commit, we revert the default value for nocookie-udp-size back to
4096 because the option is too obscure and most people don't realize
that they also need to change this configuration option in addition to
max-udp-size.
Since the queries sent towards root and TLD servers are now included in
the count (as a result of the fix for CVE-2020-8616),
"max-recursion-queries" has a higher chance of being exceeded by
non-attack queries. Increase its default value from 75 to 100.
Upon request from Mark, change the configuration of salt to salt
length.
Introduce a new function 'dns_zone_checknsec3aram' that can be used
upon reconfiguration to check if the existing NSEC3 parameters are
in sync with the configuration. If a salt is used that matches the
configured salt length, don't change the NSEC3 parameters.
This commit adds stub parser support and tests for:
- "tls" statement, specifying key and cert.
- an optional "tls" keyvalue in listen-on statements for DoT
configuration.
Documentation for these options has also been added to the ARM, but
needs further work.
The DNS Flag Day 2020 aims to remove the IP fragmentation problem from
the UDP DNS communication. In this commit, we implement the required
changes and simplify the logic for picking the EDNS Buffer Size.
1. The defaults for `edns-udp-size`, `max-udp-size` and
`nocookie-udp-size` have been changed to `1232` (the value picked by
DNS Flag Day 2020).
2. The probing heuristics that would try 512->4096->1432->1232 buffer
sizes has been removed and the resolver will always use just the
`edns-udp-size` value.
3. Instead of just disabling the PMTUD mechanism on the UDP sockets, we
now set IP_DONTFRAG (IPV6_DONTFRAG) flag. That means that the UDP
packets won't get ever fragmented. If the ICMP packets are lost the
UDP will just timeout and eventually be retried over TCP.
Certain parts of the existing documentation for the "rrset-order"
statement are incorrect, others are ambiguous. Rework the relevant
section of the ARM to make it clear and up-to-date with the source code.
No issues with the glue cache feature have been reported since its
introduction in BIND 9.12. As the rationale for introducing the
"glue-cache" option was to have a safety switch readily available in
case the glue cache turns out to cause problems, it is time to deprecate
the option. Glue cache will be permanently enabled in a future release,
at which point the "glue-cache" option will be made obsolete.
The current serve-stale implementation in BIND 9 stores all received
records in the cache for a max-stale-ttl interval (default 12 hours).
This allows DNS operators to turn the serve-stale answers in an event of
large authoritative DNS outage. The caching of the stale answers needs
to be enabled before the outage happens or the feature would be
otherwise useless.
The negative consequence of the default setting is the inevitable
cache-bloat that happens for every and each DNS operator running named.
In this MR, a new configuration option `stale-cache-enable` is
introduced that allows the operators to selectively enable or disable
the serve-stale feature of BIND 9 based on their decision.
The newly introduced option has been disabled by default,
e.g. serve-stale is disabled in the default configuration and has to be
enabled if required.
There were some missing bits in the other rst files and Makefile.am(s)
that didn't reflect the rename of the main document. Also add
ddns-confgen.8 manpage.
