In theory a TTL of one day is not an issue if Name Servers are changed to another server with an identical zone file.
That is almost never the case. Changes to resource records are nearly always made at the same time as the delegation is changed.
In practice the reason for changing Name Servers is usually "something is broken" e.g. a dispute and the provider has dumped the zone.
We find most requests relate to a business decision to change service provider, although above certainly occurs :-)
The problem being that caching resolvers will cache the fact that a zone doesn't have any usable Name Servers (Hmm, remember Microsoft), so it takes 24 hours before a broken zone will burst back in to life.
Yep, not to mention mail being delivered to mail servers that are no longer configured to accept mail for a domain, and web sites that are off the air for a time longer than they need to be. Some folk may suggest change the RR's in the old name servers first then change delegation later. In the old days when technical clue and cooperation was alive and well this is a reasonable suggestion. Not these days! regards Peter Mott Chief Enthusiast 2DAY INTERNET LIMITED It's kind of fun to do the impossible - Walt Disney -/- - To unsubscribe from nznog, send email to majordomo(a)list.waikato.ac.nz where the body of your message reads: unsubscribe nznog