[ntp:questions] Random Observation

Richard Thomas rbthomas at cs.rutgers.edu
Sun Jun 25 09:57:38 UTC 2017


Hi Bob,

It appears that you are right.  Observe that “us.pool.ntp.org” just gives IPv4 addresses — the same 4 addresses in random order.
I presume that the particular set of 4 addresses will be a slowly varying function of time: wait an hour and you’ll get a different group of 4.  though I haven’t done that experiment.

But “2.us.pool.ntp.org” gives 4 IPv4 addresses and 4 IPv6 addresses.

I assume it’s a deliberate choice, but I have no idea what the reasoning behind it might be…

> almini:~ rbthomas$ host us.pool.ntp.org
> us.pool.ntp.org has address 154.16.245.246
> us.pool.ntp.org has address 209.133.217.165
> us.pool.ntp.org has address 50.112.150.45
> us.pool.ntp.org has address 71.248.190.29

> almini:~ rbthomas$ host us.pool.ntp.org
> us.pool.ntp.org has address 71.248.190.29
> us.pool.ntp.org has address 50.112.150.45
> us.pool.ntp.org has address 209.133.217.165
> us.pool.ntp.org has address 154.16.245.246

> almini:~ rbthomas$ host 2.us.pool.ntp.org
> 2.us.pool.ntp.org has address 104.131.53.252
> 2.us.pool.ntp.org has address 204.2.134.162
> 2.us.pool.ntp.org has address 142.4.196.99
> 2.us.pool.ntp.org has address 66.135.44.92
> 2.us.pool.ntp.org has IPv6 address 2600:3c00::f03c:91ff:fe91:5dd8
> 2.us.pool.ntp.org has IPv6 address 2604:a880:800:10::1:9001
> 2.us.pool.ntp.org has IPv6 address 2001:470:0:2c8::2
> 2.us.pool.ntp.org has IPv6 address 2607:fcd0:100:c21::1f2a:e81b
> almini:~ rbthomas$ 
> 

Enjoy!
Rick

On Jun 22, 2017, at 7:33 AM, Bob McDonald <bmcdonaldjr at gmail.com> wrote:

> It seems as though when I use a config similar to the following I get no
> IPv6 servers in my pool selections.
> 
> pool us.pool.ntp.org iburst
> pool north-america.pool.ntp.org iburst
> pool pool.ntp.org iburst
> 
> only when I add a number prefix (as below) to the entries do I get IPv6
> servers in my candidate list.
> 
> pool 2.us.pool.ntp.org iburst
> pool 2.north-america.pool.ntp.org iburst
> pool 2.pool.ntp.org iburst
> 
> Do I just not understand what *should* be configured?
> 
> Regards,
> 
> Bob
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