Simple definition

Duration of response DNS Can stay in hiding.

Technical definition

Duration of response DNS In a professional environment, this mechanism usually integrates with other services to control the speed of propagation perceived during a change DNS.

What is it used for?

control the speed of propagation perceived during a change DNS.

Practical example

before migration, the TTL a recording.

Common issues

missing or incorrect recording
cache DNS still active
Incoherent delegation or authoritative server

Key takeaway: Always adapt the diagnosis to the product version and the architecture actually deployed.