IPv6 AAAA records

I follow the development of IPv6 in particular, it is interesting when at last we will begin to issue prefixes to end users. Until now, only MTU has owned / 32 pefix since February, other major operators have not been seen. In August, Rambler and Yandex received prefkis. You can track issued SixxS prefixes. So I wanted to check the site with an IPv6 host, for example ipv6.google.com, we do

# dig ipv6.google.com

; << >> DiG 9.5.0-P2 << >> ipv6.google.com
;; global options: printcmd
;; Got answer:
;; - >> HEADER << - opcode: QUERY, status: NOERROR, id: 52452
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0
')
;; QUESTION SECTION:
; ipv6.google.com. IN A

;; ANSWER SECTION:
ipv6.google.com. 10800 IN CNAME ipv6.l.google.com.

;; AUTHORITY SECTION:
l.google.com. 60 IN SOA algoogle.com. dns-admin.google.com. 1355383 900 900 1800 60

;; Query time: 33 msec
;; SERVER: 127.0.0.1 # 53 (127.0.0.1)
;; WHEN: Wed Aug 27 15:54:41 2008
;; MSG SIZE rcvd: 102

We are asked to make an additional request.

#dig ipv6.l.google.com

; << >> DiG 9.5.0-P2 << >> ipv6.l.google.com
;; global options: printcmd
;; Got answer:
;; - >> HEADER << - opcode: QUERY, status: NOERROR, id: 14957
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
; ipv6.l.google.com. IN A

;; AUTHORITY SECTION:
l.google.com. 60 IN SOA elgoogle.com. dns-admin.google.com. 1355383 900 900 1800 60

;; Query time: 19 msec
;; SERVER: 127.0.0.1 # 53 (127.0.0.1)
;; WHEN: Wed Aug 27 15:56:21 2008
;; MSG SIZE rcvd: 83

For a while, it put me in a stupor. there is no answer and as we see status: NOERROR
Especially for me it was strange to see such answers when I for example made such a request.

# dig ya.ru aaaa

; << >> DiG 9.5.0-P2 << >> ya.ru aaaa
;; global options: printcmd
;; Got answer:
;; - >> HEADER << - opcode: QUERY, status: NOERROR, id: 9892
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
; ya.ru. IN AAAA

;; AUTHORITY SECTION:
ya.ru. 900 IN SOA ns1.yandex.ru. sysadmin.yandex.ru. 2008081100 10800 900 2592000 900

;; Query time: 74 msec
;; SERVER: 127.0.0.1 # 53 (127.0.0.1)
;; WHEN: Wed Aug 27 15:59:13 2008
;; MSG SIZE rcvd: 79


There is no error, but there is no answer either. It seemed to me immediately obvious that it was the software’s concern to use the AAAA or A record. those. If the answer to AAAA record is empty and without error, then there is an A record and vice versa. If you write software, be careful.