Re: NAT Multihoming

[Stephen Satchell <list () satchell net>]

Chris Owen wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> 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).