1. DNS/query_type/any

RFC 8482

• Providing Minimal-Sized Responses to DNS Queries That Have QTYPE=ANY

https://datatracker.ietf.org/doc/html/rfc8482

The main difference here is that the TC bit SHOULD NOT be set in the
response, thus indicating that this is not a complete answer.

1.1. cloudflare.com

https://blog.cloudflare.com/deprecating-dns-any-meta-query-type/

Today, we are announcing that we are deprecating the DNS ANY meta-query.
 In a few weeks we'll be responding to those queries with rcode 4 / Not Implemented.

To cite a DNS guru Andrew Sullivan:

In general, ANY is useful for troubleshooting but should never be used for regular operation. 
Its output is unpredictable given the effects of caches.
It can return enormous result sets.

https://docs.citrix.com/ko-kr/netscaler/11-1/dns/dns-any-query.html

https://isc.sans.edu/forums/diary/DNS+ANY+Request+Cannon+Need+More+Packets/13261/

https://tools.ietf.org/html/draft-ietf-dnsop-refuse-any-04

https://tools.ietf.org/html/rfc2181

-- ToshinoriMaeno 2017-06-15 00:35:04

1.2. citrix product

http://docs.citrix.com/ja-jp/netscaler/11-1/dns/dns-any-query.html

• The ANY query must be sent to a name server that is authoritative for a domain.

Behavior in ADNS Mode

In the ADNS mode, the NetScaler appliance returns the records held in its local cache. If there are no records in the cache, the appliance returns the NXDOMAIN (negative) response.

DNS protection from ANY query amplification attacks¶ https://clouddocs.f5.com/api/irules/DNS-protection-from-ANY-query-amplification-attacks.html