Changing IP-block

[Barry Margolin]

In article <m3em7b5pld.fsf at rancid.apocalypse.no>,
Pål Sollie <sollie at saint-etienne.no> wrote:
>I'm administrating two small nameservers (one class C IP-range and a
>couple of domains). In a few months we'll be switching providers. How
>should I best prepare myself for the change? The nameservers will also
>be assigned new IP's. As this is a low-budget operation, funded by the
>city, I don't have too much hardware available, so I'll have to make
>it work with the two servers I use today. Should I adjust the TTL and
>expire-records some time in advance? What about moving one server at a
>time? I can probably arrange to put one of the servers over on the new
>providers net some time in advance, as these are low-traffic
>servers. Any ideas are welcome.

Moving them one at a time would probably be the easiest solution.  That
way, while you're waiting for the old address of the server that was moved
to time out of caches, the one that stayed put will still be reachable.
After that address change has propagated, you can then move the second
server, and while its old address is still in caches the server that was
moved first will be reachable.

You probably don't have much control over the TTLs of the NS records,
because the registrar that administers the parent domain (the .NO domain, I
presume) probably has an automated system that assigns the same TTL to all
the delegation records.  However, you should reduce the TTLs of the records
for all the machines in your domain whose IP addresses will be changing as
a result of the move.

Do *not* reduce the Expire time.  This record has nothing to do with how
long it takes for old records to expire, that's what TTL is for.  Expire
specifies how long a slave server will continue to be authoritative when it
has been unable to refresh the zone.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Burlington, MA
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