WEBVTT

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Why might a DNS change not appear immediately everywhere?

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Resolvers can reuse cached answers according to their time to live.

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Understand the cached answer.
6 DNS TTL basics.

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TTL means time to live
For DNS, it describes the cache lifetime associated with a record.
DNS record · Cached answer · Cache lifetime

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Caching avoids repeat lookups
A resolver can reuse an answer while its cache rules allow it.
Stored answer · Repeat request · Reuse period

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Record changes need context
A resolver may still hold an earlier answer after the source changes.
Updated source record · Earlier cached value · Remaining lifetime

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Lowering it is not retroactive
A shorter new TTL does not instantly remove previously cached answers.
Previous TTL · Existing caches · Planned timing

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Use the provider settings
Available values and special handling can differ by record and provider.
Record type · Provider limits · Supported setting

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Verify the actual result
Check authoritative records and relevant resolver answers during a change.
Authoritative answer · Cached resolver answer · Working service

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Your checklist
TTL means time to live · Caching avoids repeat lookups · Record changes need context · Lowering it is not retroactive · Use the provider settings · Verify the actual result

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Plan changes around the existing records and their cache lifetimes.
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