How to get a subset of NTP servers from *.pool.ntp.org

ntp

I am doing some reliability tests and needed a list of NTP servers from fr.pool.ntp.org (or any other geographic or national pool).

I queried the pool 100 times but only got 13 unique servers (out of the 255 available for FR). This is expected as this is how DNS cache works and will be enough for the tests but I wonder what would be a better to directly get a subset of the pool server IPs.

I did not find them published on ntp.org (this is not needed for clients who will query [0-3].<something>.pool.ntp.org but since there are activity graphs I though that there could be a more detailed list).

The list is not confidential as it is indirectly queried via DNS, though I can understand concerns about potential DoS or whatever should a complete one be available.

So: are there such lists and if not – why?

Best Answer

You can find out about the pool at http://www.pool.ntp.org/.

I queried the pool 100 times but only got 13 unique servers (out of the 255 available for FR).

The DNS server for the NTP Pool brings hosts in and out of the available DNS over time. For example, my host gets brought into the available pool for a 15 minute slot every few hours.

I did not find [a list of servers] published on ntp.org [...]

You could ask on the NTP Pool mailing list. I'm not sure you'll be given the current definitive list, though, but it might be worth asking. I'm happy to offer my server as an NTP Host but I'm not sure I would want it in a published list.

Disclaimer: I provide one of the NTP servers for the UK pool. I do this "because I can". I am not a Pool Administrator.

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