On 10/20/07, Lee Sharp <leesharp at hal dash pc dot org> wrote:
> Some do recognize TTL and some don't. Set the ttl for 5 minutes about 6
> hours before the change. Once it is stable, set it back to 4 hours.
> And recognize that some providers will ignore what you do. (However,
> all of the ones I have seen respect TTL)
From my experience with domains I manage that are highly trafficked
(100K+ daily page loads) from dozens of countries, like pfsense.org,
most DNS servers (> 99%) do obey TTL's. There will be that fraction of
a percent that won't for a day or two, and potentially a very small
number that will take longer than that.
To the original poster, best you can do is as others have recommended,
lower your TTL prior to the change. Once it's working on the new line
and you're satisfied it's stable, raise your TTL again. Unless you
have thousands of people around the world accessing your site, you're
highly unlikely to run into even a single DNS server that doesn't obey
TTL, so you shouldn't have any problems.