I was a bit confused by this article, since the NTP pools do not currently support NTS (last I checked at least). So, I spun up a Plucky install to have a look.
pool 1.ntp.ubuntu.com iburst maxsources 1 nts prefer
pool 2.ntp.ubuntu.com iburst maxsources 1 nts prefer
pool 3.ntp.ubuntu.com iburst maxsources 1 nts prefer
pool 4.ntp.ubuntu.com iburst maxsources 1 nts prefer
You'll note that the domain is no longer ntp.org. Further down in the file is this:
# If you can't or won't use NTS, then here are the old NTP-only definitions
#pool ntp.ubuntu.com iburst maxsources 4
#pool 0.ubuntu.pool.ntp.org iburst maxsources 1
#pool 1.ubuntu.pool.ntp.org iburst maxsources 1
#pool 2.ubuntu.pool.ntp.org iburst maxsources 2
So, as I suspected, they are no longer using the NTP pool servers. Having a look at dig:
It seems like you get two different regions with the NTS setup, UK and US. Doing some queries against the NTS instances, they are all stratum 2. Doing some queries against the NTP pool, there is a mix of S1 to S3. Of course, with the NTP pool, there are a ton of different hosts spread out across a large geographic region. Also, the pool monitors the different instances and automatically removes false/down tickers from the pool - so not using the pool does comes with some loss of functionality. Of course, I have no idea how the *.ntp.ubuntu.com instances are configured. They are all S2 - so perhaps they are still getting the same S1 time source as the pool. It seems the trade off made for the added security is a loss of regional diversity and perhaps some automatic fail-over handling that is provided by the pool. It would be nice if NTS support could be added to the pool so that we could have the best of both worlds.
I was a bit confused by this article, since the NTP pools do not currently support NTS (last I checked at least). So, I spun up a Plucky install to have a look.
/etc/chrony/sources.d/ubuntu-ntp-pools.sources contains:
You'll note that the domain is no longer ntp.org. Further down in the file is this: So, as I suspected, they are no longer using the NTP pool servers. Having a look at dig: It seems like you get two different regions with the NTS setup, UK and US. Doing some queries against the NTS instances, they are all stratum 2. Doing some queries against the NTP pool, there is a mix of S1 to S3. Of course, with the NTP pool, there are a ton of different hosts spread out across a large geographic region. Also, the pool monitors the different instances and automatically removes false/down tickers from the pool - so not using the pool does comes with some loss of functionality. Of course, I have no idea how the *.ntp.ubuntu.com instances are configured. They are all S2 - so perhaps they are still getting the same S1 time source as the pool. It seems the trade off made for the added security is a loss of regional diversity and perhaps some automatic fail-over handling that is provided by the pool. It would be nice if NTS support could be added to the pool so that we could have the best of both worlds.