about a query

[Terry.]

Hello,

Please see the dig info below. ns1.dns-diy.com is the auth-server of
duowan.com domain.
My question is, when ns1.dns-diy.com answer with a CNAME for
"udb.duowan.com", and the answer also include an A RR for that alias,
how will the public DNS cache servers handle this answer?
Will the DNS cache use this A RR as result directly, or they make a
new request for the alias domain name udb.duowan.blogchina.org and
find the result?

Thanks!

$ dig udb.duowan.com +trace

; <<>> DiG 9.4.2-P2 <<>> udb.duowan.com +trace
;; global options:  printcmd
.                       108212  IN      NS      d.root-servers.net.
.                       108212  IN      NS      e.root-servers.net.
.                       108212  IN      NS      m.root-servers.net.
.                       108212  IN      NS      b.root-servers.net.
.                       108212  IN      NS      g.root-servers.net.
.                       108212  IN      NS      l.root-servers.net.
.                       108212  IN      NS      c.root-servers.net.
.                       108212  IN      NS      i.root-servers.net.
.                       108212  IN      NS      k.root-servers.net.
.                       108212  IN      NS      a.root-servers.net.
.                       108212  IN      NS      j.root-servers.net.
.                       108212  IN      NS      h.root-servers.net.
.                       108212  IN      NS      f.root-servers.net.
;; Received 512 bytes from 202.96.128.86#53(202.96.128.86) in 4 ms

com.                    172800  IN      NS      h.gtld-servers.net.
com.                    172800  IN      NS      g.gtld-servers.net.
com.                    172800  IN      NS      e.gtld-servers.net.
com.                    172800  IN      NS      c.gtld-servers.net.
com.                    172800  IN      NS      d.gtld-servers.net.
com.                    172800  IN      NS      a.gtld-servers.net.
com.                    172800  IN      NS      l.gtld-servers.net.
com.                    172800  IN      NS      f.gtld-servers.net.
com.                    172800  IN      NS      k.gtld-servers.net.
com.                    172800  IN      NS      b.gtld-servers.net.
com.                    172800  IN      NS      i.gtld-servers.net.
com.                    172800  IN      NS      m.gtld-servers.net.
com.                    172800  IN      NS      j.gtld-servers.net.
;; Received 492 bytes from 128.8.10.90#53(d.root-servers.net) in 340 ms

duowan.com.             172800  IN      NS      ns1.dns-diy.com.
duowan.com.             172800  IN      NS      ns2.dns-diy.com.
;; Received 204 bytes from 192.35.51.30#53(f.gtld-servers.net) in 300 ms

udb.duowan.com.         90000   IN      CNAME   udb.duowan.blogchina.org.
udb.duowan.blogchina.org. 5     IN      A       64.38.63.4
;; Received 86 bytes from 218.85.139.33#53(ns1.dns-diy.com) in 19 ms

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