digで、なんかANSER SECTIONがないとき

$ dig yahoo.co.jp

; <<>> DiG 9.10.3-P4-Debian <<>> yahoo.co.jp
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: FORMERR, id: 27249
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; WARNING: EDNS query returned status FORMERR - retry with '+noedns'

;; QUESTION SECTION:
;yahoo.co.jp.                   IN      A

;; Query time: 0 msec

よく読むと

;; WARNING: EDNS query returned status FORMERR - retry with '+noedns'

と書いてあるので、+noedns をつけて再挑戦する。

$ dig yahoo.co.jp +noedns

; <<>> DiG 9.10.3-P4-Debian <<>> yahoo.co.jp +noedns
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 63082
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;yahoo.co.jp.                   IN      A

;; ANSWER SECTION:
yahoo.co.jp.            228     IN      A       182.22.59.229
yahoo.co.jp.            228     IN      A       183.79.135.206

;; Query time: 0 msec