nslookup 或 dig print recursion not available 警告

Issue

当查询 DNS 资源记录时，在 dig 或 nslookup 的输出中打印出类似如下的消息：

# nslookup some.host.example.com
;; Got recursion not available from 192.0.2.1, trying next server
;; Got recursion not available from 198.51.100.1, trying next server
Server:         203.0.113.1
Address:        203.0.113.1#53

Name:   some.host.example.com
Address: 192.0.2.101
;; Got recursion not available from 192.0.2.1, trying next server
;; Got recursion not available from 198.51.100.1, trying next server