Net Speed set to 512 Kbit/s: still in global zone, but almost no traffic

Server operators
4

Hi

I am not running the pool but just a server operator who does some monitoring so others may have a different point of view.

I am reading that to be that you only want requests from ip addresses in Italy. My answer would be no it is not possible - that I know of.

The problem is that when the pool receives a DNS request for pool.ntp.org it needs to work out where the request is coming from so it can reply with what it thinks is a nearby NTP server ip addresses. The pool uses GeoDNS to work that out but the problem is GeoDNS is not that reliable in picking the source location based on the ip address. For example if a user in France makes a request and the pool thinks the source ip address is in Italy then it could send the request from France to your Itialian server. Think of it this way - A user in France makes a DNS request to Cloudflare. The France Cloudflare site is under mantenance so the anycast request ends up going to Cloudflare Italy which looks in its cache and/or asks the pool. The pool “thinks” the request is from Italy so replies with your server IP address in Italy.

Take https://community.ntppool.org/t/problems-with-cloudflare-dns-in-nz/3512 for example. A while back asking Cloudflare for an NTP server from New Zealand would return addresses from Argentina.

Another example is that every few hours I ask the pool DNS servers where they think a request is coming from. A sample of the results from yesterday for an Alibaba server in Manila -

======== Pool Geodns guess for for ph-mnl-alibaba...
      6  8.8.8.8 ph asia @
      4  9.9.9.9 us north-america @
      2  9.9.9.9 ph asia @
      5  1.1.1.1 ph asia @
      1  1.1.1.1 hk asia @

All six of the requests to Google DNS said the source ip was in Manila. Asking Quad9 and 4 of the 6 requests said the request was from the US with 2 in Manila. For Cloudflare 5 in Manila and one in Hong Kong.

Based on that I do not think it would be possible to restrict your server to only receive requests from inside Italy if that was the question you were asking :grinning_face: