Resolve CNAME feature behavior changed in 31.x versions
Article ID: 434706
Updated On:
Products
Issue/Introduction
When Resolve CNAME knob is checked under a GSLB service and the GSLB pool member configured with an FQDN is selected, Avi DNS VS will resolve the CNAME to an A record. In the DNS response, both the CNAME and A record will be sent to the client.
In 22.1.x and 30.x versions, this resolved A record was provided in the Answer Section of the DNS response.
However, starting 31.x version, this A record is now provided in the Additional Section of the DNS response.
This change can impact legacy DNS client/applications which expect the resolved CNAME to be under the Answer Section of the DNS response.
Sample response for 22.1.x and 30.x versions:
root@ubnt-server:~# dig test.new-domain.abc.com @10.91.6.78
; <<>> DiG 9.18.39-0ubuntu0.24.04.2-Ubuntu <<>> test.new-domain.abc.com @10.91.6.78
;; global options: +cmd
;; Got answer:
;; WARNING: .local is reserved for Multicast DNS
;; You are currently testing what happens when an mDNS query is leaked to DNS
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 36854
;; flags: qr aa rd; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;test.new-domain.abc.com. IN A
;; ANSWER SECTION:
test.new-domain.abc.com. 30 IN CNAME google.com.
google.com. 30 IN A xx.xx.xx.xx
;; Query time: 3 msec
;; SERVER: 10.91.6.78#53(10.91.6.78) (UDP)
;; WHEN: Tue Mar 17 21:45:02 UTC 2026
;; MSG SIZE rcvd: 98
Sample response for 31.2.1 and 31.2.2 versions:
root@ubnt-server:~# dig test.new-domain.abc.com @10.91.6.116
; <<>> DiG 9.18.39-0ubuntu0.24.04.2-Ubuntu <<>> test.new-domain.abc.com @10.91.6.116
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27854
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 2
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;test.new-domain.abc.com. IN A
;; ANSWER SECTION:
test.new-domain.abc.com. 30 IN CNAME google.com.
;; ADDITIONAL SECTION:
google.com. 30 IN A xx.xx.xx.xx
;; Query time: 1 msec
;; SERVER: 10.91.6.116#53(10.91.6.116) (UDP)
;; WHEN: Tue Mar 17 18:43:37 UTC 2026
;; MSG SIZE rcvd: 89
Environment
31.1.x, 31.2.1 and 31.2.2
Cause
This change in behavior was introduced when adding support for SRV record type.
Resolution
This issue will be fixed in 31.2.3, 32.1.1 version.
Bug ID: AV-269550
There is no workaround available for this issue in 31.x.
If you have started seeing this issue after upgrading to 31.x from 22.1.x or 30.x release, you will have to rollback to the earlier release train.
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