Blackhole server

This is especially helpful because a second lookup for the same address performed by the same node would probably be answered from the local cache instead of querying the authoritative servers again.

[8] Because the load on the IANA blackhole servers became very high, an alternative service, AS112, has been created, mostly run by volunteer operators.

The AS112 project is a group of volunteer name server operators joined in an autonomous system.

They run anycasted instances of the name servers that answer reverse DNS lookups for private network and link-local addresses sent to the public Internet.

The decision was made by a small subset of root server operators to run the reverse delegations; each announcing the network using the autonomous system number of 112.