What happens when you update your DNS

Re:What happens when you update your DNS by closeparen on Monday June 22, 2020 @07:19PM (#23608104)

Traceroute’s trick is amusing. It abuses the TTL field, sending out packets with too-low TTLs and waiting to see who complains about them. When layers reveal themselves they are doing it voluntarily, and those wise to the game can choose not to participate, or to troll it.

https://www.theregister.com/2013/02/15/star_wars_traceroute/

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Re:What happens when you update your DNS by m3047 on Monday June 22, 2020 @08:24PM (#23608604)

Those are IP packet TTLs. Also useful in some cases for diagnosing mysterious RSTs and SYNs. Also useful in some cases to purposefully set low if there is route flapping.

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Re:What happens when you update your DNS by allarm on Tuesday June 23, 2020 @03:48AM (#23610996)

The IP TTL field is unrelated to the topic - DNS and IP are sitting on the different OSI layers. Also, the traceroute command does not abuse this field, it’s just the way the IP protocol works. I.e. eBGP sets TTL to 1 by default, to prevent establishing relationships with the neighbors further that one hop away.

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Re:What happens when you update your DNS by Tepix on Tuesday June 23, 2020 @02:54AM (#23610655)

It's not abusing the TTL, it's working as designed

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Re:What happens when you update your DNS by closeparen on Tuesday June 23, 2020 @03:03AM (#23610699)

AFAIK the design purpose of TTL is to prevent an infinite loop in case the route contains a cycle.

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