On Wed, Apr 16, 2014 at 2:25 PM, Jimmy Hess <mysi...@gmail.com> wrote: > It's not hard to use WHOIS to lookup the registrar of each of the > nameservers for proofpoint.com > (ns1.proofpoint.us, ns3.proofpoint.us). > > Long TTLS are appropriate for a production zone, but in my > estimation, it is improper for > a registrar to impose or select by default a TTL longer than 1 hour, > for a newly published or newly changed zone. > > The TTL can and should be reasonably low initially and > automatically increased gradually over time, > only after the zone has aged with no record changes and confidence is > increased > that the newly published zone is correct.
There was a study on an unrelated topic a presented at a NANOG or ARIN meeting a few years back. I don't recall the exact details. The interesting bit was the analysis they did on DNS caching to see the impact from varying the TTL. I don't remember the exact numbers, but short TTLs exhibited only a small increase in query rate over long ones. There's really no driving need to set the TTL higher than 1 hour, ever, under any circumstances. -Bill -- William D. Herrin ................ her...@dirtside.com b...@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
