only the response has aa flag can be cached?

[pyh at mail.nsbeta.info]

Hello, 

I'm not sure about, is it true that only the response which has included 
the "aa" in flags can be cached by client DNS Cache? 

For example, for my domain, there are two queries below, the result for the 
first query won't be cached, but the second will be cached, am I right? 

$ dig mail.nsbeta.info ns @ns34.domaincontrol.com 

; <<>> DiG 9.4.2-P2 <<>> mail.nsbeta.info ns @ns34.domaincontrol.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12892
;; flags: qr rd; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 2
;; WARNING: recursion requested but not available 

;; QUESTION SECTION:
;mail.nsbeta.info.              IN      NS 

;; ANSWER SECTION:
mail.nsbeta.info.       1800    IN      NS      dwdns2.nsbeta.info.
mail.nsbeta.info.       1800    IN      NS      dwdns1.nsbeta.info. 

;; ADDITIONAL SECTION:
dwdns2.nsbeta.info.     3600    IN      A       219.129.239.5
dwdns1.nsbeta.info.     3600    IN      A       120.132.133.48 

 -------------------------------------------------- 

$ dig mail.nsbeta.info ns @dwdns2.nsbeta.info 

; <<>> DiG 9.4.2-P2 <<>> mail.nsbeta.info ns @dwdns2.nsbeta.info
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 28561
;; flags: qr aa rd; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available 

;; QUESTION SECTION:
;mail.nsbeta.info.              IN      NS 

;; ANSWER SECTION:
mail.nsbeta.info.       3600    IN      NS      dwdns1.nsbeta.info.
mail.nsbeta.info.       3600    IN      NS      dwdns2.nsbeta.info.