Today, we released version 4.1.21 of the authoritative DNS name server NSD.
This release introduces query type ANY refusal. NSD already has RRL support that by default throttles queries, and also queries of type ANY. But an nsd.conf option has been added, this makes NSD refuse queries of type ANY.
The tcp-count can be higher. For more tcp service, use something like tcp-count: 10000 or so. The fix is that tcp connections use (much) less memory now, than in previous versions.
The memclean option is for memory checkers and code analyzers, without the option, NSD lets the system remove memory pages with unused resources on exit of a process, which is much faster.
You can get binary and source packages of this version from the downloads page.