[hexa-]

Those come from a WHOIS daemon that is reachable in the network as whois.dn42. There's also an authoritative DNS system for the .dn42 TLD with anycasted resolvers

    % dig whois.dn42 @resolver.nic.dn42 any +short
    172.22.0.43
    fd42:d42:d42:43::

as well as some ACME implementation with a CA that is constrained to the .dn42 domain and the allocated IP space.

   % openssl x509 -in /etc/ssl/certs/dn42_Root_Authority_CA.pem -noout -text
    [...]
                X509v3 Name Constraints:
                    Permitted:
                      DNS:.dn42
                      IP:172.20.0.0/255.252.0.0
                      IP:FD42:0:0:0:0:0:0:0/FFFF:0:0:0:0:0:0:0
    [...]

So there's quite some stuff to do and learn about.