bind , unbound レスポンス 違い 調査中

今までたいして気にしてなかったけど、bind , unbound 応答内容まちまちだなー。
これって何なんだろう。。answer があればリゾルバは平気なのかな。
うーん、ルールがいまいちわからん。。

unbound は:
glue が同じドメインだと、question , answer , auth , additonal ? ( yahoo のケース )
glue が異なるドメインだと、question , answer , auth ? ( pearljam のケース )
CNAME だと、question , answer ? ( google , facebook のケース )

bind は:
glue が同じドメインだと、question , answer , auth ? ( yahooのケース )
glue が異なるドメインだと、question , answer , auth , additonal ? ( pearljam のケース )
CNAME だと、question , answer , auth ? ( google , facebook のケース )

なの?

[ google ]

unbound 1.3.3

;; QUESTION SECTION:
;www.google.com. IN A

;; ANSWER SECTION:
www.google.com. 603811 IN CNAME www.l.google.com.
www.l.google.com. 1 IN A 66.249.89.99
www.l.google.com. 1 IN A 66.249.89.147
www.l.google.com. 1 IN A 66.249.89.104
www.l.google.com. 1 IN A 66.249.89.103

BIND 9.6.1-P1-RedHat-9.6.1-9.P1.fc12

question , answer , auth section 。

;; QUESTION SECTION:
;www.google.com. IN A

;; ANSWER SECTION:
www.google.com. 604800 IN CNAME www.l.google.com.
www.l.google.com. 300 IN A 66.249.89.104
www.l.google.com. 300 IN A 66.249.89.147
www.l.google.com. 300 IN A 66.249.89.99
www.l.google.com. 300 IN A 66.249.89.103

;; AUTHORITY SECTION:
l.google.com. 86400 IN NS d.l.google.com.
l.google.com. 86400 IN NS a.l.google.com.
l.google.com. 86400 IN NS b.l.google.com.
l.google.com. 86400 IN NS e.l.google.com.
l.google.com. 86400 IN NS g.l.google.com.
l.google.com. 86400 IN NS f.l.google.com.

[ 大好きな、pearljam のサイト ]

unbound

;; QUESTION SECTION:
;www.pearljam.com. IN A

;; ANSWER SECTION:
www.pearljam.com. 300 IN A 69.25.141.2

;; AUTHORITY SECTION:
pearljam.com. 300 IN NS ns-c.pnap.net.
pearljam.com. 300 IN NS ns-b.pnap.net.
pearljam.com. 300 IN NS ns-a.pnap.net.
pearljam.com. 300 IN NS ns-d.pnap.net.


bind

;; QUESTION SECTION:
;www.pearljam.com. IN A

;; ANSWER SECTION:
www.pearljam.com. 300 IN A 69.25.141.2

;; AUTHORITY SECTION:
pearljam.com. 300 IN NS ns-c.pnap.net.
pearljam.com. 300 IN NS ns-b.pnap.net.
pearljam.com. 300 IN NS ns-d.pnap.net.
pearljam.com. 300 IN NS ns-a.pnap.net.

;; ADDITIONAL SECTION:
ns-a.pnap.net. 172800 IN A 64.94.123.4
ns-b.pnap.net. 172800 IN A 64.94.123.36
ns-c.pnap.net. 172800 IN A 64.95.61.4
ns-d.pnap.net. 172800 IN A 64.95.61.36


[ facebook ]

unbound

;; QUESTION SECTION:
;www.facebook.com. IN A

;; ANSWER SECTION:
www.facebook.com. 30 IN CNAME www.facebook.com.edgesuite.net.
www.facebook.com.edgesuite.net. 5400 IN CNAME a2047.w7.akamai.net.
a2047.w7.akamai.net. 20 IN A 61.113.95.89
a2047.w7.akamai.net. 20 IN A 61.113.95.81
a2047.w7.akamai.net. 20 IN A 61.113.95.65

bind

;; QUESTION SECTION:
;www.facebook.com. IN A

;; ANSWER SECTION:
www.facebook.com. 30 IN CNAME www.facebook.com.edgesuite.net.
www.facebook.com.edgesuite.net. 5400 IN CNAME a2047.w7.akamai.net.
a2047.w7.akamai.net. 20 IN A 61.113.95.43
a2047.w7.akamai.net. 20 IN A 61.113.95.50

;; AUTHORITY SECTION:
w7.akamai.net. 1799 IN NS n2w7.akamai.net.
w7.akamai.net. 1799 IN NS n7w7.akamai.net.


[ yahoo ]

unbound

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

;; ANSWER SECTION:
www.yahoo.co.jp. 300 IN A 203.216.243.218
www.yahoo.co.jp. 300 IN A 203.216.247.225
www.yahoo.co.jp. 300 IN A 203.216.247.249

;; AUTHORITY SECTION:
yahoo.co.jp. 900 IN NS dnsg01.yahoo.co.jp.
yahoo.co.jp. 900 IN NS ns04.ops.ogk.yahoo.co.jp.

;; ADDITIONAL SECTION:
dnsg01.yahoo.co.jp. 900 IN A 211.14.12.10
ns04.ops.ogk.yahoo.co.jp. 900 IN A 124.83.218.185


bind

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

;; ANSWER SECTION:
www.yahoo.co.jp. 300 IN A 124.83.147.205
www.yahoo.co.jp. 300 IN A 124.83.167.212

;; AUTHORITY SECTION:
yahoo.co.jp. 900 IN NS dnsg01.yahoo.co.jp.

pink floyd のベストいいなー。いろんなアルバムからの寄せ集めなのに、
違和感をまったく感じない。high hopes すきだー。
the grass was greener , the light was brighter ...
出だしの鐘の音とピアノすきだ。最後のギターソロもすきだ～。