[Discuss] DNSSEC

[Richard Pieri]

On 12/7/2014 10:58 AM, Edward Ned Harvey (blu) wrote:
> What happens if the local DNS caching server is old and doesn't
> support DNSSEC?  What if the client has support for DNSSEC, sets
> DO=1, and the caching server is old and doesn't know anything about
> DNSSEC?  Hopefully an old dns server is able to dumbly relay
> information that it doesn't understand.

According to early DNSSEC design discussions, backwards compatibility 
and co-existence with so-called insecure DNS is an explicit requirement 
[RFC 3833 -> Galvin93].

According to RFC 3597, a properly functioning resolver MUST pass on 
unknown records as unstructured binary data (read: no changes are 
permitted). RFC 3597 was written specifically to address the issue of 
insecure resolvers passing DNSSEC RRs.

According to me, the answer to your followup question is this: given a 
resolver that pre-dates RFC 3597 or does not implement RFC 3597 for some 
technical reason (Internet of Things constraints perhaps?), you cannot 
rely on it to pass DNSSEC RRs.

-- 
Rich P.