google DNS does not contain ECS(client subnet) sometimes

[김성주]

Below is the Google DNS query including ECS to my authoritative name server.

Below is the Google DNS query without ECS to my authoritative name server.

I have question. why this situation happened? 

I really want to know this problem.

please. help me. thank you.

[Alex Dupuy]

Please see the instructions at https://developers.google.com/speed/public-dns/docs/ecs.

Your name servers are not meeting the requirements outlined in that document, which need to be followed for Google Public DNS to auto-detect ECS support.