High Latency Spikes

Hey

I live in Israel. most of the time I get good 2-3 ms latency. ( Fiber optic connection 1000/100 )

Running ping -t to dns.nextdns.io will give me high spikes every few packets sent.

Running ping -t to 1.1.1.1 is consistent even during the NextDNS spikes so its not connection related.

Running ping -t to ping.nextdns.io is good as well (3-4ms)

So I don't really know what's going on

How can I address / fix it ?

Thanks