[BIND 8.2] Negative TTL not working ???

Barry Margolin barmar at bbnplanet.com
Wed Nov 17 16:48:40 UTC 1999


In article <199911170539.QAA18211 at bsdi.dv.isc.org>,
 <Mark_Andrews at iengines.com> wrote:
>	Go read RFC 2308 and look at the new use for the minimum field
>	and why $TTL was added.  The answer above is a negative answer,
>	and the TTL is correct.

In particular, the following from section 5:

   Like normal answers negative answers have a time to live (TTL).  As
   there is no record in the answer section to which this TTL can be
   applied, the TTL must be carried by another method.  This is done by
   including the SOA record from the zone in the authority section of
   the reply.  When the authoritative server creates this record its TTL
   is taken from the minimum of the SOA.MINIMUM field and SOA's TTL.
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The interesting thing is that section 3 says that the receiver is supposed
to use the minimum of the SOA's TTL and the SOA.MINIMUM field as the
negative cache time.  It seems redundant for both the caching server and
the authoritative server to perform the calculation min(SOA.MINIMUM, SOA'S
TTL).

-- 
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.


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