Changing parent provider

[Barry Margolin]

In article <3.0.5.32.19990621084833.00acf610 at relay.waycom.com.ar>,
Fernando Ronci  <fernando at waycom.com.ar> wrote:
>We run our ISP and our servers are authoritative for our zone.
>On July, 11th, we'll change our parent provider, which means
>all our IP addresses will change too.
>Considering that we are authoritative for waycom.com.ar and
>NIC-AR is authoritative for com.ar, (NIC-AR is the only entity
>that refers resolvers quering xxxx.com.ar to the authoritative
>nameserver of the queried zone) my consult is:
>How long before changing the namservers IP addresses should we
>update records on NIC-AR with the new addresses?
>Are there any other considerations to take into account?
>We want to avoid loosing mails sent to our domain or having our
>www sites unreachable.
>(The TTL in our SOA record is two days)

The best thing to do is try to arrange for both addresses to work in
parallel for a few days.  You can do this if you can connect to the new
provider before disconnecting the old one, and configure multiple addresses
on the DNS server.  Add the address in the new provider's block to the DNS
server.

As soon as the new connection is up, submit the nameserver change to
NIC-AR.  After a day or two the old addresses should have timed out of
caches and you can remove the old address from the server.

BTW, if you had an off-site secondary server you wouldn't have as much of a
problem.  Its address wouldn't change, so you could depend on it during the
transition period.

-- 
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
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