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TTL - Glossary | MDN 1/3 https://developer.mozilla.org/en-US/docs/Glossary/TTL reference web, html, css, javascript, documentation 2026-05-05T05:46:52.294634+00:00 kb-cron

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  1. Glossary
  2. TTL

TTL

Time To Live (TTL) can refer to either the lifetime of a packet in a network, or the expiry time of cached data.

In this article

Networking

In networking, the TTL, embedded in the packet, is a usually defined as a number of hops or as an expiration timestamp after which the packet is dropped. It provides a way to avoid network congestion, but releasing packets after they roamed the network too long.

Caching

In the context of caching, TTL (as an unsigned 32-bit integer) being a part of the HTTP response header or the DNS query, indicates the amount of time in seconds during which the resource can be cached by the requester.

See also