[dns-operations] DNS prefetching, DLV and cheap NAT router state table overflow

[Florian Weimer]

I did some additional experiments, and here is what I found:

I could not reproduce this with a close-by external resolver (with DLV
still enabled).  Of course, Unbound sends no hardening queries for
infrastructure records when working as a forwarder.  So I suspect the
phenomenon has little impact on DNSSEC validation on end hosts.

The state table issue is not related to DNS at all, it happens with
other UDP packets, too.

I could reproduce it with a warmed-up cache, too, by visiting web
pages such as <http://www.norid.no/domenenavnbaser/domreg.html>.