v4:
dig @8.8.8.8 www.qq.com +subnet=108.165.64.0/24
v6:
dig @2001:4860:4860::8888 www.qq.com +subnet=2400:8d60:13::/56
google常用的DNS有: 8.8.8.8 8.8.4.4 2001:4860:4860::8844 2001:4860:4860::8888
腾讯的DNS也好用: 119.29.29.29
需要注意的是: v4里边最小的掩码是24, V6里边最小的掩码是56, 否则可能会出现如下提示EDE: 49152: (Provided ECS includes 64 bits, but no more than 56 are allowed. https://developers.google.com/speed/public-dns/docs/ecs)