DNS · Website glossary

DNS TTL

Quick answer · What is DNS TTL?

Time to live specifies how long a DNS answer may remain in a cache before it needs refreshing.

IN PRACTICE

DNS TTL: an example

A resolver can continue using an earlier answer for the remaining lifetime of the cached record.

KEEP IN MIND

Lowering a TTL does not retroactively shorten copies already cached with the previous value.

Put the idea to work

Frequently asked questions

What is a practical example of DNS TTL?

A resolver can continue using an earlier answer for the remaining lifetime of the cached record.

Does lowering TTL shorten copies that are already cached?

Lowering a TTL does not retroactively shorten copies already cached with the previous value.

Which concepts should I read alongside DNS TTL?

DNS cache: A temporary store of DNS answers kept to avoid repeating the same lookup immediately.
DNS propagation: An informal name for the period in which changed DNS data becomes visible through different servers and caches.