[ntp:questions] Compensating for asymmetric delay on a per-peer/server basis?
nomail at example.com
Fri Sep 12 08:42:32 UTC 2014
Martin Burnicki <martin.burnicki at meinberg.de> wrote:
> Rob wrote:
>> Martin Burnicki <martin.burnicki at meinberg.de> wrote:
>>> - NAT doesn't hurt at all, unless you are trying to use NTP's authentication
>> NAT in itself does not hurt, but when you want to be a timeserver for
>> a large number of clients, it can be a problem.
>> Many home routers have no "static NAT" but only "portforwarding" which
>> creates dynamic NAT entries on demand. As UDP has no session concept,
>> such NAT entries have a lifetime of usually a couple of minutes.
>> When you serve thousands of clients, this tends to overflow the NAT
>> table or stress the lookup code so much that it overloads the CPU.
> Haven't had such case, yet since my home NTP server doesn't serv 1000s
> of clients, but sounds reasonable and should be kept in mind.
It is sometimes a problem when you become member of the NTP pool.
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