network change

[Eric A. Hall]

> When we had the first network move to the current provider, we had
> trouble with DNS. People for outside our network had difficulty
> connecting to certain site because the old DNS data was still being
> looked up. I'm wondering if any of you have a better solution and
> perhaps can give me advise.

The data was probably stuck in various caches. You have two options on
your next changeover. The first one is to start shortening the TTL
values of your DNS data so that it does not get cached for as long. By
the time you get ready for your changeover, have the TTL down to 30
minutes or some other small value so that the data expires quickly. You
will still have some problems but not that many and not for very long.
You will need to time this right, as you don't want to have queries
being answered with TTL of 2 weeks the day before the transition.

Another option is to run both networks simultaneously and gradually
migrate the DNS pointers to the new addresses. Harder but definitely a
smoother way to transition.

-- 
Eric A. Hall                                      http://www.ehsco.com/
Internet Core Protocols        http://www.oreilly.com/catalog/coreprot/