Tim Shoppa wrote:
Rob Jannsen said:
This leads to a large number of different
systems that each query the time only
once or a few times.
I thought that this was a "model citizen" usage
pattern for end-users. It's the bozos that query
me every second that are the bad apples in my
book.
True.
The request peaks tend to be
considerable, probably due to the relatively
static content of the DNS zone (they all get
the same timeservers at some point in time).
Are they all trying to query at the top of every
hour or something like that? It's a stupid polling
pattern
No, what I mean is that the DNS servers, instead of rotating the
available NTP servers at each request and thus distributing the load
among all available servers, send the same zone information for an hour
or so.
So, when your server is in the DNS zone you get a lot of "newcomer"
requests. Clients that use a real NTP implementation will find your
server address when they reboot or otherwise restart their NTP client
and then will remain with you, so they are a constant load. But because
of the way that the DNS works, you get (some fraction of) all one-shot
queries during the period that your server address is in the set of
addresses handed out by DNS.
As has been discussed before, this could be changed by using a more
dynamic DNS server for the pool.
Rob
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