Originally posted by: Garion
All these answers are generally correct, but there's one very important fact that's missing..
DNS is controlled by TTL's - Time To Lives. Each domain has a TTL that is used by DNS servers across the Internet. This TTL controls how long the DNS servers will cache information about your domain - What the authoritative DNS servers are, etc. If you set a one-week TTL (not uncommon) and move your domain it might take up to a week for the zone to expire in some DNS servers. The TTL is part of the DNS zone information and is something you can change. If you are planning on moving your domain, it's wise to set the TTL down loaw (~1 hour or so) a few weeks before you move, then set it back up once you've moved it to your new provider. Don't keep it low, as that adds undue load to your resolving DNS servers and the Internet as a whole
- G