nanog mailing list archives

Re: Dyn DDoS this AM?


From: Masood Ahmad Shah <masoodnt10 () gmail com>
Date: Sat, 22 Oct 2016 13:22:45 +1100


On Oct 21, 2016, at 6:35 PM, Eitan Adler <lists () eitanadler com> wrote:

[...]

In practice TTLs tend to be ignored on the public internet. In past
research I've been involved with browser[0] behavior was effectively
random despite the TTL set.

[0] more specifically, the chain of DNS resolution and caching down to
the browser.


Yes, but that it can be both better and worse than your TTLs does not mean
that you can ignore properly working implementations.

If the other end device chain breaks you that's their fault and out of
your control.  If your own settings break you that's your fault.


+1 to what George wrote that we should make efforts to improve our part of
the network. There are ISPs that ignore TTL settings and only update their
cached records every two to three days or even more (particularly the
smaller ones). OTOH, this results in your DNS data being inconsistent but
it’s very common to cache DNS records at multiple levels. It's an effort
that everyone needs to contribute to.



Sent from my iPhone


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