Prepare for IP Change

[Kevin Darcy]

Jon Booth wrote:

> In the next week or two we are going to change our network setup and
> anumber of hosts in a number of zones are going to have their IP changed.
> What are some good tips to prepare for this? I was thinking of reducing
> the TTL right down for each zone. Will this help?

Yes. Although you really only need to reduce the TTLs on the A records that
are going to change. It would be wasteful to reduce the TTLs on
*all* records in the zone(s), if many of them are going to stay the same.

Also, do any of the IP changes apply to nameservers? If so, then you'll need
to co-ordinate those IP changes with the registrar of any domain delegated
to those nameservers -- the "glue" A records in the parent domain's
nameservers will probably need to be updated, as well as the A records that
you maintain in your zone(s). Be aware that the TTL values on TLD records is
typically 2 days. So it could take that long for everyone to see the change
of address. This is why when moving nameservers it is often advisable to
move them in multiple stages, rather than all at once, or to temporarily set
up one or more non-moving nameservers (e.g. your ISP's) to function as the
authoritative servers for the zone(s) during the transition.


- Kevin