> Does anybody know what the best procedure is to minimize downtime when
> switching providers? We are switching our providers which means we will
> need to modify our dns servers and all the domains since we have new IPs.
> Does anybody know of a resource/information/etc that could help me in
> switching IPs. Do we simply just modify the IP of our primary DNS to the
> new IP and all the other domains using that as the primary will follow suit?
> Any help would be appreciated...
Yes, do this:
1. Looking at the SOA record for all your domains, find the Refresh
interval (I will call it R1).
2. Change the TTL (also in SOA) for all your domains to 30 seconds
(A plan '30' will do, seconds is the default time unit).
3. Increase your serial number (as always)
4. Wait. You will have to wait R1 hours (or days, depending on what
the value of R1 is) for all the caching name servers around the
world to expire your data. Once they pull your new zone data (with
your new TTL value), they will think "Hey, this zone needs to be
refreshed every 30 seconds, so I will cache data for only 30
seconds." At this point, all your IP numbers are still the same and
your sites are still up, so you can wait longer if needed.
5. Change providers, servers, IP numbers, etc... As soon as you are
situated with your new IPs, change the address records for all your
domains and increase the SOA serial number. Now, since all the
caching name servers around the world keep your data for only 30
seconds, they will grab your new IPs almost immediately.
6. Change the TTL for all your domains back to a reasonable value
('1D' for me).
Using this method, your downtime will only be the length of your
travel (if you're physically moving servers) and server
reconfiguration time.
Let me know how it goes...
--
Garry Dolley (Programmer/Managing Partner)
ARP Networks (http://www.arpnetworks.com)
Providing IT Services Around The Globe.
