DNS Negative Caching
Barry Margolin
barmar at alum.mit.edu
Fri Aug 28 19:49:23 UTC 2015
In article <mailman.2601.1440783131.26362.bind-users at lists.isc.org>,
"Darcy Kevin (FCA)" <kevin.darcy at fcagroup.com> wrote:
> What's in a name? :-)
>
> RFC 2308 said that the use of the last field of the SOA to set
> negative-caching TTL is "the new defined meaning of the SOA minimum field".
> So you can *call* it "minimum", but it is *actually* supposed to function as
> something else...
>
> Eventually I hope BIND will conform to the spirit of RFC 2308 and stop using
> the last field of the SOA to set the default TTL, as a "fallback" in
> scenarios where the file would otherwise be illegal (i.e. the first RR has no
> explicit TTL set, and there is no $TTL directive preceding it). RFC 2308 is
> so old, that if it were a person, it would be legal to buy cigarettes in some
> parts of the world. It's long past time for folks to get with the program.
Does the RFC specify some other default TTL if there's no $TTL
directive? If not, the software needs to do something, and using the old
method for compatibility is as good anything else (on the assumption
that anyone who didn't put $TTL in the file was depending on this use of
the SOA record).
--
Barry Margolin
Arlington, MA
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