[olug] Domain name propagation - how long?

[Ryan O'Rourke]

On Tue, 2003-10-28 at 16:36, Sean Kelly wrote:
> On Tue, Oct 28, 2003 at 12:59:15PM -0600, Trent Melcher wrote:
> > I think they update the root server twice a day everyday. So a registered
> > domain could start working in no later than 12 hours I believe.  The
> > propagation does take some time after the root servers are updated, so it
> > could take 1 -2 days for it to completely propagate, it all depends on how
> > pepole have their DNS servers configured.  THe quickest I had a domain
> > actually work was in about 3 hours, but I got it registered just before the
> > root servers were schedule to do their updates.
> 
> First off, DNS is not a server-push protocol. When you register a domain,
> it is not necessary for it to propagate out across the entire internet. In
> fact, when a client asks a nameserver to resolve 'xyzzy.net', if the
> nameserver doesn't have it in its cache, it will go to the root servers and
> ask about it. So, it is only necessary for the root servers to be updated
> in order for a domain to "start working" on the Internet. There is no one
> to two day waiting period while things "propagate".

What about when you change webhosts and have to update your DNS through
your registrar? Internet DNS servers already have your domain mapped to
1.2.3.4 - how long does it take after your registrar updates for
Internet DNS servers to realize that your domain is now mapped to
5.6.7.8?