Classless reverse zones CNAME and PTR resolution issue

[Nagesh Thati]

Hello,
I am facing an issue with CNAME and PTR records resolution issues when
classless reverse zones are defined in the BIND 9.16.* version (Without
recursion), but it used to work in 9.11.* version (Without recursion).
Below example shows what reverse zones are created and how the dig output
is giving,

*named.conf:*
*recursion no;*






*zone "22.10.13.in-addr.arpa" IN {        type master;        file
"/var/named/zones/masters/db.22.10.13.in-addr.arpa";        check-names
ignore;        zone-statistics yes;};*





*zone "0-25.22.10.13.in-addr.arpa" IN {        type master;        file
"/var/named/zones/masters/db.0-25.22.10.13.in-addr.arpa";
check-names ignore;        zone-statistics yes;};*

*db.22.10.13.in-addr.arpa:*











*$TTL    1200$ORIGIN 22.10.13.in-addr.arpa.22.10.13.in-addr.arpa.  IN
 SOA     remote1.india.com <http://remote1.india.com>.
admin.india.com <http://admin.india.com>. (                2022102807 ;
serial                21600 ; refresh                3600 ; retry
      604800 ; expire                86400 ; minimum        )        IN
 NS      remote1.india.com
<http://remote1.india.com>.0-25.22.10.13.in-addr.arpa.     IN      NS
 remote1.india.com <http://remote1.india.com>.2.22.10.13.in-addr.arpa.
   1200            IN              CNAME   2.0-25.22.10.13.in-addr.arpa.*

*db.0-25.22.10.13.in-addr.arpa*










*$TTL    1200$ORIGIN 0-25.22.10.13.in-addr.arpa.0-25.22.10.13.in-addr.arpa.
    IN      SOA     remote1.india.com <http://remote1.india.com>.
admin.india.com <http://admin.india.com>. (                2022102808 ;
serial                21600 ; refresh                3600 ; retry
      604800 ; expire                86400 ; minimum        )        IN
 NS      remote1.india.com
<http://remote1.india.com>.2.0-25.22.10.13.in-addr.arpa.   1200
 IN              PTR     3G00051Phone.india.com
<http://3G00051Phone.india.com>.*

*DIG Output:*






















*[root at remote1]# dig @localhost -x 13.10.22.2; <<>> DiG 9.16.30 <<>>
@localhost -x 13.10.22.2; (2 servers found);; global options: +cmd;; Got
answer:;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32110;; flags:
qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1;; WARNING:
recursion requested but not available;; OPT PSEUDOSECTION:; EDNS: version:
0, flags:; udp: 1232; COOKIE:
f29427e34cd79c0101000000635fe20b8accc09065ab6b33 (good);; QUESTION
SECTION:;2.22.10.13.in-addr.arpa.       IN      PTR;; ANSWER
SECTION:2.22.10.13.in-addr.arpa. 1200   IN      CNAME
2.0-25.22.10.13.in-addr.arpa.;; Query time: 1 msec;; SERVER:
127.0.0.1#53(127.0.0.1);; WHEN: Mon Oct 31 14:56:11 GMT 2022;; MSG SIZE
 rcvd: 122*

I am getting the answer as only CNAME, not getting the exact A record for
that IP address. This used to work in BIND 9.11.* version, recently I
upgraded to 9.16.* latest version and from that I am facing this issue.


But when I enable the recursion on BIND 9.16.* then I am getting the
expected answer as below,






















*[root at remote1]# dig @localhost -x 13.10.22.2; <<>> DiG 9.16.30 <<>>
@localhost -x 13.10.22.2; (2 servers found);; global options: +cmd;; Got
answer:;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40386;; flags:
qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1;; OPT
PSEUDOSECTION:; EDNS: version: 0, flags:; udp: 1232; COOKIE:
8cee7aad934beda401000000635fe32bf7ce38d08006dbd1 (good);; QUESTION
SECTION:;2.22.10.13.in-addr.arpa.       IN      PTR;; ANSWER
SECTION:2.22.10.13.in-addr.arpa. 1200   IN      CNAME
2.0-25.22.10.13.in-addr.arpa.2.0-25.22.10.13.in-addr.arpa. 1200 IN   PTR
  3G00051Phone.india.com <http://3G00051Phone.india.com>.;; Query time: 0
msec;; SERVER: 127.0.0.1#53(127.0.0.1);; WHEN: Mon Oct 31 15:00:59 GMT
2022;; MSG SIZE  rcvd: 165*

Can someone help me why this behaviour is seen on BIND 9.16.* version.
Thanks,
Nagesh
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