On Tue, 3 Apr 2001, Garry Dolley wrote:
> > Does anybody know what the best procedure is to minimize downtime when
> > switching providers?
>
> 2. Change the TTL (also in SOA) for all your domains to 30 seconds
> (A plan '30' will do, seconds is the default time unit).
>
> 4. Wait. You will have to wait R1 hours (or days, depending on what
> the value of R1 is) for all the caching name servers around the
> world to expire your data.
Having gone through this a couple of times, I can tell you that this
*almost* works. The problem is that a small percentage of ISP's
nameservers don't play by the rules, i.e. they will substitute their own
values for the TTL. One case in particular I recall used 7 days
regardless of the TTL broadcast by the authoritative server.
In that vein, also be aware that quite a few nameservers have been
configured to use secondary nameservers as primaries, I suppose in the
theory that secondaries will be faster than primaries. Don't depend on
changing your primary first and getting secondaries later. Do them all as
close to simultaneously as you can.
Cliff
