William Brown wrote:
In businesses, it's also common place to have a low-ish ttl (Say
minutes) and when a system is migrated, they swap the A/AAAA records to
the new system. The dns servers on the network are updated, but the
workstation has the old record cached. Without a local cache, they
would query the local server again, which is relatively cheap. IE: It
keeps users happier even if they only needed to wait 5 minutes. Some
people like things to be instant.
If the admins on that network configured a five-minute TTL, it's because
they *want* the clients to cache the records for five minutes. They can
set the TTL to zero if they want the servers to be queried for every
And if they're migrating a system they will know this more than five
minutes in advance, so they can set a zero TTL temporarily.