Re: [Ntp] Draft agenda and date for NTP wg virtual interim.

On 30 Mar 2020, at 12:17, Ragnar Sundblad wrote:

>> On 30 Mar 2020, at 10:10, Miroslav Lichvar <mlichvar@redhat.com> 
>> wrote:
>>
>> On Fri, Mar 27, 2020 at 05:47:38PM +0100, Ragnar Sundblad wrote:
>>>> On 27 Mar 2020, at 17:41, Watson Ladd <watson@cloudflare.com> 
>>>> wrote:
>>>> Corporate firewalls might have problems with random ports.
>>>
>>> Yes, there is no single easy solution as far as I know. :-(
>>>
>>> I would prefer if the ISP:s could stop size blocking port 123. But I
>>> don’t know if that is realistic.
>>
>> An ISP told me they would have to replace an expensive piece of HW to
>> block only the amplification-prone modes (6 and 7). I suspect some of
>> the "anti-DDoS" midleboxes have the packet matching in the silicon 
>> and
>> care only about the NTP port number.
>>
>>> Rate limiting I think we must accept, maybe encourage as an 
>>> alternative.
>>
>> NTS works poorly if there is a large packet loss. Too many NTS-KE
>> requests.
>
> Yes, if they throw away more than 7/8 of the traffic for a long time,
> there will likely be a new KE exchange. Hopefully that does not happen
> very often.
>
> Ragnar
>

I think it is too early to conclude that NTS-KE will fail because of 
rate limitations. Up to now there is not enough data available for a 
serious forecast. My own experience is that I didn’t experience any 
issue at all. But that said, it is clear that this might not be 
representative.

Dieter

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