[as112-ops] DNS Blackhole servers requests question

[Roberto Carna]

Dear, I want to use and test the DNS BLACKHOLE servers for RFC 1918
network addresses:

BLACKHOLE-1.IANA.ORG (192.175.48.6)
BLACKHOLE-2.IANA.ORG (192.175.48.42)

But every time I query these servers, I can’t reach them.

Are they running? Or maybe they don’t work for every people from Internet?

In all my attempts to query these blackhole servers, just one time I
get a NXDOMAIN valid response.

Always I can’t reach them:

root at MITLPDNS01:~# host -t NS 10.IN-ADDR.ARPA 192.175.48.6
;; connection timed out; no servers could be reached

root at MITLPDNS01:~# host -t NS 10.IN-ADDR.ARPA 192.175.48.42
;; connection timed out; no servers could be reached

Please can you help me?

I know I can create local DNS zones for RFC 1918 networks in my BIND
server, but I want to understand the use of DNS Blackhole servers.

Thanks in advance, regards!!!