May 2017
Beginner
552 pages
28h 47m
English
Content preview from Linux Shell Scripting Cookbook - Third Edition
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Time to live
Each ping packet has a predefined number of hops it can take before it is dropped. Each router decrements that value by one. This value shows how many routers are between your system and the site you are pinging. The initial Time To Live (TTL) value can vary depending on your platform or ping revision. You can determine the initial value by pinging the loopback connection:
$> ping 127.0.0.1 64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.049 ms $> ping www.google.com 64 bytes from 173.194.68.99: icmp_seq=1 ttl=45 time=49.4 ms
In this example, we ping the loopback address to determine what the TTL is with no hops (in this case, 64). Then we ping a remote site and subtract that TTL value from our No-Hop value to determine how ...