Download Knot Resolver 4.0.0

Knot Resolver is an open source DNS recursor written in C and LuaJIT. When you perform a dns lookup, a recursor initially starts asking the lookup query to a dns root server. This can then redirect to other servers, from where it can redirect to other servers and so on, until finally a server is reached that knows the answer or knows that the look-up is not possible. The latter can be the case if the name does not exist or the servers do not respond. cloudflare uses Knot Resolver for example for its 1.1.1.1 dns service. The developers of CZ NIC have released version 4.0.0 with the following changes:

Knot Resolver 4.0.0 released

Incompatible changes

• see upgrading guide:
• configuration: trust_anchors aliases .file, .config() and .negative were removed (!788)
• configuration: trust_anchors.keyfile_default is no longer accessible (!788)
• daemon: -k/–keyfile and -K/–keyfile-ro options were removed
• meson build system is now used for builds (!771)
• build with embedded LMBD is no longer supported
• default modules dir location has changed
• DNSSEC is enabled by default
• upstream packages for Debian now require systemd
• libknot >= 2.8 is required
• net.list() output format changed (#448)
• net.listen() reports error when address-port pair is in use
• bind to DNS-over-TLS port by default (!792)
• stop versioning libkres library
• default port for web management and APIs changed to 8453

Improvements

• policy.TLS_FORWARD: if hostname is configured, send it on wire (!762)
• hints module: allow configuring the TTL and change default from 0 to 5s
• policy module: policy.rpz() will watch the file for changes by default
• packaging: lua cqueues added to default dependencies where available
• systemd: service is no longer auto-restarted on configuration errors
• always send DO+CD flags upstream, even in secure zones (#153)
• cache.stats() output is completely new; see docs (!775)
• improve usability of table_print() (!790, !801)
• add DNS-over-HTTPS support (#280)
• docker image supports and exposes DNS-over-HTTPS

Bug fixes

• predict module: load stats module if config didn’t specify period (!755)
• trust_anchors: don’t do 5011-style updates on anchors from files that were loaded as unmanaged trust anchors (!753)
• trust_anchors.add(): include these TAs in .summary() (!753)
• policy module: support ‘#’ for separating port numbers, for consistency
• fix startup on macOS+BSD when
• policy.RPZ: log problems from zone-file level of parser as well (#453)
• fix flushing of messages to logs in some cases (notably systemd) (!781)
• fix fallback when SERVFAIL or REFUSED is received from upstream (!784)
• fix crash when dealing with unknown TA key algorithm (#449)
• go insecure due to algorithm support even if DNSKEY is NODATA (!798)
• fix mac addresses in the output of net.interfaces() command (!804)
• http module: fix too early renewal of ephemeral certificates (!808)

Module API changes

• kr_straddr_split() changed API a bit (compiler will catch that)
• C modules defining *_layer or *_props symbols need to change a bit See the upgrading guide for details. It’s detected on module load.