Every DNS record carries a TTL value (in seconds) that tells resolvers how long they can cache the answer. Common defaults:
- 300 seconds (5 min) — quick changes; expect more load on your nameservers
- 3600 seconds (1 hour) — balanced default; what most providers use
- 86400 seconds (24 hours) — very stable records; reduces resolver load but slows changes
The "DNS is slow to change" feeling comes from TTL: when you update a record, every resolver in the world is still serving the OLD value until their cached copy expires.
Pro tip for planned changes:
- Lower the TTL to 300 seconds (5 min) at least one TTL-cycle before the change. This makes the next change propagate within minutes.
- Wait at least the original TTL duration (e.g., 1 hour if it was set to 3600).
- Make the actual change.
- After 24 hours, raise the TTL back to a normal value to reduce resolver load.
The shorter the TTL, the more frequently resolvers query your authoritative nameservers. For most domains the load is negligible; for heavily-trafficked ones, lower TTLs add real cost (especially if your DNS provider charges per query).
