What is DNS TTL, and when should you change it?

Read the unit and the existing value

DNS editors often display TTL in seconds or as a labelled preset. Check which one your provider uses. A value of 3600 seconds is one hour; it describes caching of that record, not how long a registrar takes to process a nameserver change.

Some services choose an automatic value or manage TTL differently for proxied records. Use the options supported by your actual DNS host rather than copying a number from an unrelated tutorial. Record the current value before modifying it.

Lower it before the planned move

If a record currently has a long TTL, reduce it sufficiently ahead of the change for previously cached answers to age out. Lowering it at the same instant as the destination change does not retroactively shorten copies already held elsewhere.

For example, a website move can be easier to observe when the relevant records have shorter cache lifetimes in advance. Keep the old host available during the transition if your migration plan calls for it. DNS preparation does not replace testing the new host first.

Use a simple preparation sequence

This is a planning pattern, not a promise that every network updates at the same moment.

• Identify the exact records that will change.
• Record their values and current TTLs.
• Choose a supported lower TTL in advance if useful.
• Wait for the old cache lifetime before the planned destination change.
• Update and verify authoritative answers.
• Restore an appropriate normal TTL after the service is stable.

Do not use TTL as a cure for an incorrect record

A low TTL cannot fix an IP address that points at the wrong host or a missing email record. It only changes caching behaviour. Check the data and active nameservers before adjusting timing settings.

Keep TTL changes in the same log as the website or email move. The domain registration itself remains a separate responsibility: maintain its contact details and renewal date even when the technical setup is working well.