Question about internal 'private' servers

[Hans Mayer]

Hi Dave,

I am not sure if you understand how a pool is working. Or probably it's 
me that I don't understand you ?
If you define a pool like at.pool.ntp.org you get always 4 different IP 
addresses and also a different set of IP adresses.
Check it out with command "dig at.pool.ntp.org" several times.

For example in AT there are 4 pools from 1.at.pool.ntp.org till 
4.at.pool.ntp.org
So theoretically you could use the 4 from your country. ( in my case AT 
is Austria )
2.at.pool.ntp.org is the only one which has IPv6 addresses too. So if 
you have IPv6 too you should use a number "2" server.
And the advantages of using a pool is the fact you get only really 
working NTP server addresses and no dead ones.
Therefore if you use some pools there is no need to change any DNS.
In the pools you get hopefully only stratum 2 servers and higher. In 99% 
good enough. If you want to use a stratum 1 you have to define it as 
server. And the netiquette says, one should ask the operator if it's 
allowed to use it.

// Hans

-- 



On 16.01.25 17:04, Dave Hall via users wrote:
> Hal,
>
> Some further updates and thoughts:
>
> Regarding the tos minclock config line:  I checked one of my systems 
> that's still running Debian 11 and regular NTP. This system was quite 
> happy with only two servers.  So my original 
> two-maaster-server configuration was OK (but not great) until I 
> upgraded to NTPSEC.  This is not a complaint - just me understanding 
> how the problem crept in on me.
>
> Regarding the number of local masters:  I completely understand why 4 
> is a realistic minimum.  Now that this has been pointed out to me I 
> will plan to move back to 4 or more in the very near future.  Last 
> night, due to other pressing issues, I just needed to get my clocks 
> synchronized without thinking about (planning for) which additional 
> hosts to use as masters.
>
> Regarding my question about using a local POOL, my idea is that I 
> could change the pool membership via DNS without having to touch a 
> config file on each system.  So a pool of 2 servers does seem 
> pointless, but when I add 3 or 4 more it will be easy.
>
> -Dave
>
> --
> Dave Hall
> Binghamton University
> kdhall at binghamton.edu
>
> On Wed, Jan 15, 2025 at 10:31 PM Hal Murray <halmurray at sonic.net> wrote:
>
>
>     > One last question:  What does it take to define a POOL?  Is it
>     just a DNS
>     > name that resolves to more than one IP, or is there something more?
>
>     The general idea is that there are many servers in the pool and
>     there is
>     some smarts behind the DNS server that will rotate through the
>     servers to
>     spread the load (maybe not equally) and will monitor the available
>     servers
>     and not use any that are not responding or have a clock that is
>     way off
>     (aka broken).
>
>     More info here:
>     https://www.ntppool.org/en/
>
>     The client side will try again later when it wants more servers
>     and toss
>     out a server from the pool when it stops responding.
>
>     If you look in your log files, you will probably find lots of clutter.
>
>     In your case, with only 2 servers in the pool, I would use 2
>     server lines
>     rather than the pool.
>
>
>     -- 
>     These are my opinions.  I hate spam.
>
>
>
>
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