nanog mailing list archives
Re: AT&T / Verizon DNS Flush?
From: William Herrin <bill () herrin us>
Date: Wed, 16 Apr 2014 15:59:50 -0400
On Wed, Apr 16, 2014 at 2:25 PM, Jimmy Hess <mysidia () 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 ................ herrin () dirtside com bill () herrin us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
Current thread:
- AT&T / Verizon DNS Flush? Steven Briggs (Apr 16)
- Re: AT&T / Verizon DNS Flush? Laszlo Hanyecz (Apr 16)
- Re: AT&T / Verizon DNS Flush? Steven Briggs (Apr 16)
- Re: AT&T / Verizon DNS Flush? Valdis . Kletnieks (Apr 16)
- RE: AT&T / Verizon DNS Flush? Eric Wieling (Apr 16)
- Re: AT&T / Verizon DNS Flush? Jimmy Hess (Apr 16)
- Re: AT&T / Verizon DNS Flush? William Herrin (Apr 16)
- Re: AT&T / Verizon DNS Flush? John Peach (Apr 16)
- Re: AT&T / Verizon DNS Flush? Dennis B (Apr 21)
- Re: AT&T / Verizon DNS Flush? Steven Briggs (Apr 16)
- Re: AT&T / Verizon DNS Flush? Laszlo Hanyecz (Apr 16)
- Re: AT&T / Verizon DNS Flush? Hank Nussbacher (Apr 16)
- Re: AT&T / Verizon DNS Flush? Blake Hudson (Apr 16)