[ntp:questions] Does vendor zones also benefit from closest servers resolution?

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Thu Mar 2 03:51:02 UTC 2017


On 2017-03-01 16:11, hablutzel1 at gmail.com wrote:
>>From http://www.pool.ntp.org/en/use.html:
> Looking up pool.ntp.org (or 0.pool.ntp.org, 1.pool.ntp.org, etc) will
> usually return IP addresses for servers in or close to your country.
> For most users this will give the best results.
> And from http://www.pool.ntp.org/vendors.html#vendor-zone:
> To allow you to use the pool as the default time service in your
> application, we will set you up with special hostnames, for example
> 0.vendor.pool.ntp.org, 1.vendor.pool.ntp.org, 2.vendor.pool.ntp.org
> and 3.vendor.pool.ntp.org.
> Question is, vendor zone names resolv to closest NTP servers too?.
> For example:
> server 0.debian.pool.ntp.org iburst
> server 1.debian.pool.ntp.org iburst
> server 2.debian.pool.ntp.org iburst
> server 3.debian.pool.ntp.org iburst
> Configured in India will resolve to India's closest NTP servers?, or
> just to Debian cluster of NTP servers?.

If you run nslookup|dig|host|getent hosts on those and e.g 
{0,1,2,3}.in.pool.ntp.org from a host on the Indian internet, you should 
see a number of common IP addresses showing that the routing is geographic, 
as with the global pool.ntp.org.

The vendor pools are global aliases for branding, tracking, and reporting 
who comes in from vendors' clients.

With CC pools {0,1,2,3}.CC.pool.ntp.org will get you a pool of servers 
in *THAT* geographic location, regardless of your IP address: this may 
not be what you want if your client is not actually connected to the 
internet in that country; the same applies to regional pools e.g asia.

With vendor pools you must explicitly specify a numeric prefix 
{0,1,2,3}.VENDOR.pool.ntp.org on the DNS name(s).
With global, regional, and CC pools, you may omit the numeric prefix 
e.g. {LOC.,}pool.ntp.org and you get a pool of server addresses.

For all pools numeric prefix 2.{*.,}pool.ntp.org should get you IP V6 
addresses, but I don't know what happens if there are none in that 
country or region: may be aliased to the next more global pool.

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada


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