Maintained by: NLnet Labs

A record from cache for request that resolved to (some) CNAMEs

Mehmed Kahric
Mon Sep 21 13:17:27 CEST 2015


Hi,

I have a similar issue as reported in Bug 669.

For some (one for now) CNAMEs we have a empty A record answer from
Unbound. Proper answer came from remote DNS as showed in Unbound log and
tcpdump.
Identical issue came from both us Unbound instances:
- CentOS 6, Unbound 1.5.1 from EPEL, configured as recursive caching with
forward-zone;
- CentOS 7, Unbound 1.4.20 from base, configured as authoritative,
validating, recursive caching.

Log from first Unbound instance (with verbosity level 4) and from tcpdump
is in attachment, and dig from client (with output) is:

---
C:\Users\Moi>dig www.sensoray.com @192.168.10.14

; <<>> DiG 9.10.2-P3 <<>> www.sensoray.com @192.168.10.14
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38559
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;www.sensoray.com.              IN      A

;; ANSWER SECTION:
www.sensoray.com.       5433    IN      CNAME   sensoray.com.

;; Query time: 218 msec
;; SERVER: 192.168.10.14#53(192.168.10.14)
;; WHEN: Fri Sep 18 11:13:30 Central Europe Daylight Time 2015
;; MSG SIZE  rcvd: 59

C:\Users\Moi>dig sensoray.com @192.168.10.14

; <<>> DiG 9.10.2-P3 <<>> sensoray.com @192.168.10.14
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 5722
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;sensoray.com.                  IN      A

;; Query time: 31 msec
;; SERVER: 192.168.10.14#53(192.168.10.14)
;; WHEN: Fri Sep 18 11:13:37 Central Europe Daylight Time 2015
;; MSG SIZE  rcvd: 41

---


Regards, Mehmed
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