[dns-operations] Looking for a public blackhole/sinkhole IP address

[Stephane Bortzmeyer]

I'm trying to find out if it exists a public IP address which is a
black hole, swallowing every packet sent to it.

I can do that on my network but I'm wondering if it already exists
somewhere, may be as an anycasted service (AS112-style).

The idea is to delegate some domain names to unresponsive name servers
(deleting the domain name is less efficient, since the negative TTL is
smaller than the delegation TTL).

It must work from everywhere on the Internet. 127/8 does not (the
packets are not dropped but delivered to the resolver itself when it
will try to follow the delegation). Same thing for RFC 1918 (there are
often such addresses in the local network).

I was thinking of non-routed addresses like 198.18.0.0/15 or
203.0.113.0/24 but it's not their normal use. AFAIK, there are no
"public sinkholes" IPv4 addresses. For IPv6, there is 100::/64 but it
is only internal, there is no public 100::/64 service.