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Time to Live (TTL)

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Last updated June 24th, 2010 by Victoria Pal in Monitoring, Tech

Time To Live!We might have mentioned TTL in some of the previous posts related to Ping and Traceroute. TTL or Time To Live is the transmission limit of a given data unit in a TCP/IP or UDP-based computer network.

A data packet with a TTL value of 64 will cease to exist if it hasn't reached its end target in 64 iterations. The purpose of the TTL field is to avoid a situation in which an undeliverable datagram keeps circulating on an Internet system, a system that will eventually become swamped by such immortal datagrams.

Operation systems have different default TTL values. A detailed list of default TTL values for various operating systems can be found on The highest transmission counts of up to 40 can be observed nowadays. Initial TCP and UDP TTL for popular operating systems are usually set to at least 60 iterations.

The abbreviation "TTL" is sometimes used by people who are into OS tweaks, and in this context, it stands for "Time To Load." This alternative abbreviation of TTL should not be associated with timer values included in packets sent over TCP/IP-based networks.

To learn how TTL values are used in a computer network, please try this interactive simulation. It will help you visualize the path a data packet takes to reach its destination and return to the initial host.

We hope this interactive TTL presentation helped you to understand the process behind the words better.

Victoria Pal

She doesn't like queuing (particularly at Wimbledon). Likes traveling, tennis and reading. Loves working as a Project Manager at WebSitePulse.

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