[ntp:questions] ntpd behavior with multiple pool definitions

Dan Geist dan at polter.net
Fri Jun 16 12:36:16 UTC 2017

----- On Jun 15, 2017, at 9:28 PM, Hal Murray hmurray at megapathdsl.net wrote:

> I don't think there is any attempt to balance the usage across multiple
> pools.  It depends on the response from the DNS servers.
> If fact, I would expect it to work with 2 pools, one for inside a firewall
> that and another for outside if DNS for the internal pool only worked inside
> the firewall and the firewall blocked access to the external pool DNS or
> external NTP servers.
> Why do you need so many servers?
> You can adjust the number of clocks the pool command(s) use with tos
> maxclock.  The default is 10.  The count includes slots setup with the
> "server" command and it looks like it is counting the "pool" slot(s) too.

Hi, Hal. thanks for the clue. I don't actually want the hosts to have more than 4 or 5 resolved servers at runtime, but what I don't have currently is a way to give them that number out of a pool or 20-something and ensure a reasonably randomized answer to distribute load. That's why I'm looking into GeoDNS (for an application based way to restrict the answers based on location, "score", etc. I really just can't afford to blackhole the hosts that can't reach my resolvers on TCP53, hence the "break it into smaller chunks" aspect. 3 smaller DNS lookups instead of 1 giant one.

I'm actually going to try now with "tos maxclock" set to 7 or 8.


Dan Geist dan(@)polter.net

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