[Ntp] NTP errors

Hal Murray <hmurray@megapathdsl.net> Mon, 09 September 2019 20:29 UTC

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In-Reply-To: Message from Daniel Franke <dfoxfranke@gmail.com> of "Mon, 09 Sep 2019 12:18:01 EDT." <CAJm83bC81BWxGPmGbaTgxU6vmKtWF_-j5oMohyU9M5YX9HqbYQ@mail.gmail.com>
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Date: Mon, 09 Sep 2019 13:28:57 -0700
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Subject: [Ntp] NTP errors
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dfoxfranke@gmail.com said:
> But it's really silly for a v4 server to attempt to reply to a v5 request
> with anything but an error.

Agreed, but it's more complicated than that.  Error replies can be forged.

I think error handling needs more thought.

Another tangle in this area is rate-limiting.  With NAT, you can get 
legitimate traffic from many hosts funneled through one IPv4 address.

Are there any error-cases where the client should do something because the 
amount of trouble from not doing anything is higher than the amount of trouble 
from processing a forged packet?

"Amount of trouble" probably depends on whether you are the server or client.  
How should we think about that?

These are my opinions.  I hate spam.