Recent NTP pool traffic increase

Laurent Dumont admin at coldnorthadmin.com
Tue Dec 20 05:18:18 UTC 2016


If anything comes from this, I'd love to hear about it. As a student in 
the field, this is the kind of stuff I live for! ;)

Pretty awesome to see the chain of events after seeing a post on the 
[pool] list!

Laurent

On 12/19/2016 05:12 PM, Justin Paine via NANOG wrote:
> replying off list.
>
> ____________
> Justin Paine
> Head of Trust & Safety
> Cloudflare Inc.
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>
> On Mon, Dec 19, 2016 at 1:49 PM, Dan Drown <dan-nanog at drown.org> wrote:
>> Quoting David <opendak at shaw.ca>:
>>> On 2016-12-19 1:55 PM, Jan Tore Morken wrote:
>>>> On Mon, Dec 19, 2016 at 01:32:50PM -0700, David wrote:
>>>>> I found devices doing lookups for all of these at the same time
>>>>>
>>>>> {0,0.uk,0.us,asia,europe,north-america,south-america,oceania,africa}.pool.ntp.org
>>>>> and then it proceeds to use everything returned, which explains why
>>>>> everyone is seeing an increase.
>>>>
>>>> Thanks, David. That perfectly matches the list of servers used by
>>>> older versions of the ios-ntp library[1][2], which would point toward
>>>> some iPhone app being the source of the traffic.
>>>>
>>>> [1]
>>>> https://github.com/jbenet/ios-ntp/blob/d5eade6a99041094f12f0c976dd4aaeed37e0564/ios-ntp-rez/ntp.hosts
>>>> [2]
>>>> https://github.com/jbenet/ios-ntp/blob/5cc3b6e437a6422dcee9dec9da5183e283eff9f2/ios-ntp-lib/NetworkClock.m#L122
>>>>
>>> That would make sense - I see a lot of iCloud related lookups from these
>>> hosts as well.
>>>
>>> Also, app.snapchat.com generally seems to follow just after the NTP pool
>>> DNS lookups. I don't have an iPhone to test that though.
>>
>> Confirmed - starting up the iOS Snapchat app does a lookup to the domains
>> you listed, and then sends NTP to every unique IP.  Around 35-60 different
>> IPs.
>>
>> Anyone have a contact at Snapchat?



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