[RPZ] marking packets modified by DNS-RPZ-policy

[Florian Weimer]

* Paul Vixie:

> i can't think of a way to do this marking that won't look like a
> kashpureff attack to any downstream recursives that use the rpz
> server as a forwarder.

For DO=1 queries, a new record type would be ignored by downstream
resolvers.  Thanks to RRSIG/NSEC and later NSEC3, we've got empiric
evidence that this works (the DO flag has less to do with DNSSEC than
generally assumed).

-- 
Florian Weimer                <fweimer at bfk.de>
BFK edv-consulting GmbH       http://www.bfk.de/
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