How does DNS replication work?

[Barry Margolin]

In article <9kp7ql$ql1 at pub3.rc.vix.com>,
Christopher Dillon <monkfunk at my-deja.com> wrote:
>I've just change the IP of my domain name (as my ISP changed) and of
>course I'm waiting around for the 48 hour replication.
>
>My question is, do all the servers agree at one time to start using a
>replicated record?  Surely, a number of servers don't do bursty
>transfers and use whatever they have ...

Are you talking about the replication among the <letter>.GTLD-SERVERS.NET
servers?  I don't know the exact process, but I don't think it's feasible
for them all to switch over at the same time.  Even if they all initiate
the "ndc reload" at the same time, the machines run at different speeds so
they'll finish at different times.

But you mentioned "48 hours", which makes me think you're actually talking
about the TTL of the delegation records.  TTL controls the amount of time
that records are cached on servers all over the Internet.  The time starts
counting down at the time that a server caches the record, and different
servers will cache it at different times.  So once the change propagates to
all the GTLD servers, during the course of the following 48 hours the old
record will gradually disappear from caches around the net.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Woburn, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.