I wonder how many of the 1.3T daily requests are made by misconfigured cloud servers with no local DNS cache, hitting popular endpoints like <service>.<region>.

I wonder how many of the 1.3T daily requests are made by misconfigured cloud servers with no local DNS cache, hitting popular endpoints like <service>.<region>.amazonaws.com or fcm.googleapis.com over and over again. Consumer devices generally don't have this problem because 1) they respect the TTL, and 2) so do most ISP resolvers. Ubuntu ships systemd-resolved by default these days, which is bare-bones compared to dnsmasq but still helps reduce unnecessary DNS traffic -- not to mention precious round-trip time. You might still hit the rate limit if your app connects to more than a dozen different FQDNs within a second of starting up, but that's not a very common situation.