Karl Denninger supposedly said:
You're making lots of assumptions.
1) That client DNS systems will actually honor such a TTL. Many don't (claim they're broken all you want, but these are the facts).
2) That client SOFTWARE will actually go back and ask again for the IP number. Several won't (Netscrape being rumored to be one of them). TTLs are irrelavent in that case.
Go ahead and try to tell your customer, who purchased web service from you, that you have the right to disrupt their operations at any time and under any pretense and see how many of them you have left.
Karl, How do you handle hardware upgrades, random crashes, etc. with your clients? Do you give them a refund for such downtimes? DO you guarentee that every client that tries to access their web page will always get through? My guess is you don't. You perform a service for them and probably schedule maintenence in such a way as to minimize downtime and impact on that service. If you have a better scheme, like fully redundent machines that fall over automatically and let you do maintenence on one while the other opperates then I think you have done an excellent job at providing a quality service for your customers. On the other hand, someone who has done such a setup should realize how easy it would be to migrate it to different addresses while maintaining pretty much complete connectivity for the old addresses for a reasonable time (like a standard TTL length). ---> Phil