[97163] in North American Network Operators' Group
Re: NAT Multihoming
daemon@ATHENA.MIT.EDU (Stephen Satchell)
Sun Jun 3 22:34:40 2007
Date: Sun, 03 Jun 2007 19:33:45 -0700
From: Stephen Satchell <list@satchell.net>
To: nanog@merit.edu
In-Reply-To: <11FCCAE3-6CFA-4828-AF50-5E82F7015592@hubris.net>
Errors-To: owner-nanog@merit.edu
Chris Owen wrote:
>
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> On Jun 3, 2007, at 4:19 PM, Simon Leinen wrote:
>
>> You write "when" rather than "if" - is ignoring reasonable TTLs
>> current practice?
>
> Definitely. We've seen 15 minute TTLs regularly go 48 hours without
> updating on Cox or Comcast's name servers. I believe the most I've seen
> was 8 days (Cox).
The last time I renumbered, I found that quite a few people were not
honoring the TTLs I put in my DNS zone files. I would clone the new
address and monitor traffic to the old address -- and it took up to
seven days for the traffic to the old address to die down enough that I
could take it out. This is based on a server farm of, at the time, 162
servers.
Custom customer zone files hosted elsewhere? I had a few of those, the
effect of which is not included in the observation above.
By the way, I standardized on a customer zone TTL of 14400 (four hours)
for all zones. That provided a good balance betwen agility and master
DNS server load. rDNS is currently 172800 (two days). DNS A records
are 432000 (5 days).
