Software Update: Knot Resolver 5.1.0

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 previously released version 5.1.0 with the following changes:

Knot Resolver 5.1.0 released

Improvements

• cache garbage collector: reduce filesystem operations when idle (!946)
• policy.DEBUG_ALWAYS and policy.DEBUG_IF for limited verbose logging (!957)
• daemon: improve TCP query latency under heavy TCP load (!968)
• add policy.ANSWER action (!964, #192)
• policy.rpz support fake A/AAAA (!964, #194)

Bug fixes

• cache: missing filesystem support for pre-allocation is no longer fatal (#549)
• lua: policy.rpz() no longer watches the file when watch is set to false (!954)
• fix a strict aliasing problem that might’ve lead to “miscompilation” (!962)
• fix handling of DNAMEs, especially signed ones (#234, !965)
• lua resolve(): correctly include EDNS0 in the virtual packet (!963) Custom modules might have been confused by that.
• do not leak bogus data into SERVFAIL answers (#396)
• improve random Lua number generator initialization (!979)
• cache: fix CNAME caching when validation is disabled (#472, !974)
• cache: fix CNAME caching in policy.STUB mode (!974)
• prefill: fix crash caused by race condition with resolver startup (!983)
• webmgmt: use javascript scheme detection for websockets’ protocol (#546)
• daf module: fix del(), deny(), drop(), tc(), pass() functions (#553, !966)
• policy and daf modules: expose initial query when evaluating postrules (#556)
• cache: fix some cases of caching answers over 4 KiB (!976)
• docs: support sphinx 3.0.0+ (!978)

Incompatible changes

• minor changes in module API; see upgrading guide: https://knot-resolver.readthedocs.io/en/stable/upgrading.html