在这种情况下，A 是否比 CNAME 快得多？
$ dig www.google.com
; <<>> DiG 9.8.1-P1 <<>> www.google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 28336
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;www.google.com. IN A
;; ANSWER SECTION:
www.google.com. 13 IN A 173.194.78.103
www.google.com. 13 IN A 173.194.78.106
www.google.com. 13 IN A 173.194.78.105
www.google.com. 13 IN A 173.194.78.99
www.google.com. 13 IN A 173.194.78.147
www.google.com. 13 IN A 173.194.78.104 …