NTS pool source selection

[gombadi]

Hi

I have been playing around with the NTS pool to see how it is going (and causing some unexpected load on the systems I hear).
At the moment I have a Pi4 client running in NZ with this config

[[source]]
mode = "nts-pool"
enable-srv-resolution = true
address = "ke.sectime.org"
count = 8

Looking at the 8 pool servers being offered up I see they are all on the other side of the world. I have NTS pool servers in Auckland, NZ in Singapore and Hong Kong but none are being offered.

Some questions from this:
Does the NTS pool do any Geodns to select close sources? If not then is this planned sometime?

Looking at the pool docs it mentions First, time sources are assigned randomly, and later mentions Regions. Is there currently a way to mark a server as being in one or more regions? Is this planned?

Is a client offered up new or different servers after they do the initial pool request. For example getting 8 sources on the other side of the world then a local source joins the pool. Is it currently possible for the client to switch to the local, close by, source or will their requests always be sent to the remote sources until they reconnect to the pool?

Regards
Lyndsay

[davidv1992]

The pool does geodns. This is currently implemented as the pool finding the most specific region in which the client participates, and which is also enabled. Then afterwards the randomized process documented in the pool docs is applied.

Right now, we only have enough variation in the europe region to enable that zone. For security and load balancing, we want a significant number of servers in each region that we enable, because otherwise it would become too easy for a malicious actor to capture all trafic in a specific region, or for problematic clients to overload time servers in a specific region.

None of this is currently very visible, we should probably look at ways to make this more visible to server operators in the interface. We will look into this soon.

[mdavids]

I guess it's possible to add the entire list from https://github.com/jauderho/nts-servers to the SRV pool, but I'm not sure that would be appropriate without the operators' consent.