TTL question

Nishal Goburdhan nishal at
Tue Mar 6 09:25:21 UTC 2001

i assume you mean what's generally referred to as the cache-TTL ?
wever, what you say is not incorrect, however, bear in mind that the TTL change must happen at least one TTL period before you want the actual change to go through.

simple example:
your TTL is currently set to one day - you want to change it to one hour for faster propagation.
you need to change the TTL to one hour at least one day in advance - that way anyone that caches your domain in that interim period will have time to expire from their cache the 'old' TTL.
eg.  you make the change from 1D to 1H at 12h00 .. but at 11h59, another nameserver had queried, and will cache your domain for 1D.  

these are the nameservers that you need to allow to clear their cache.

On Tue, Mar 06, 2001 at 09:50:33AM +0100, Vincent Duquesne wrote:
> hi,
> I have one question for you,
> Can I be sure of that :
> if i put my TTL to 1 hour for instance and if I make some changes in my zone
> file, are this changes available for everybody 1 hour later max ?
> Or is there some DNS servers or gateway that doesn't match the TTL ?
> thanks in advance
> Vincent

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