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).