@Livid

docs.google.com IN CNAME writely.l.google.com

$ dig @dns.v2ex.com writely.l.google.com AAAA

; <<>> DiG 9.7.1 <<>> @dns.v2ex.com writely.l.google.com AAAA
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37571
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;writely.l.google.com. IN AAAA

;; Query time: 347 msec
;; SERVER: 178.79.131.110#53(178.79.131.110)
;; WHEN: Wed Dec 8 00:22:26 2010
;; MSG SIZE rcvd: 38



另外forward到tserv20.hkg1.ipv6.he.net可能更好，返回的地址是google在香港的服务器

$ dig @tserv20.hkg1.ipv6.he.net www.google.com AAAA

; <<>> DiG 9.7.1 <<>> @tserv20.hkg1.ipv6.he.net www.google.com AAAA
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 467
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

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

;; ANSWER SECTION:
www.google.com. 28898 IN CNAME www.l.google.com.
www.l.google.com. 22 IN AAAA 2404:6800:8005::63

;; Query time: 1607 msec
;; SERVER: 216.218.221.6#53(216.218.221.6)
;; WHEN: Wed Dec 8 00:19:27 2010
;; MSG SIZE rcvd: 80