#1051517 dnsmasq: only returns SOA for A queries on the first (going-to-upstream) query, returns empty on subsequent ones

Package:
dnsmasq
Source:
dnsmasq
Submitter:
наб
Date:
2023-09-09 00:15:04 UTC
Severity:
normal
#1051517#5
Date:
2023-09-09 00:12:25 UTC
From:
To:
Dear Maintainer,

I run dnsmasq :53 in front of unbound :5353, and:

$ read -r uuid < /proc/sys/kernel/random/uuid
$ dig a $uuid.host
;; ->>HEADER<<- opcode: QUERY; status: NXDOMAIN; id: 35035
;; Flags: qr rd ra; QUERY: 1; ANSWER: 0; AUTHORITY: 1; ADDITIONAL: 0

;; QUESTION SECTION:
;; 2a5630ac-12ac-46fa-b4c7-1fcdddfc2f8b.host.   IN      A

;; AUTHORITY SECTION:
host.                   3600    IN      SOA     ns0.centralnic.net.
hostmaster.centralnic.net. 3000457776 900 1800 6048000 3600

;; Received 124 B
;; Time 2023-09-09 02:07:26 CEST
;; From 127.0.0.1@53(UDP) in 84.1 ms
$ dig a $uuid.host
;; ->>HEADER<<- opcode: QUERY; status: NXDOMAIN; id: 1526
;; Flags: qr rd ra; QUERY: 1; ANSWER: 0; AUTHORITY: 0; ADDITIONAL: 0

;; QUESTION SECTION:
;; 2a5630ac-12ac-46fa-b4c7-1fcdddfc2f8b.host.   IN      A

;; Received 59 B
;; Time 2023-09-09 02:07:29 CEST
;; From 127.0.0.1@53(UDP) in 0.3 ms
$ dig a $uuid.host
;; ->>HEADER<<- opcode: QUERY; status: NXDOMAIN; id: 33318
;; Flags: qr rd ra; QUERY: 1; ANSWER: 0; AUTHORITY: 0; ADDITIONAL: 0

;; QUESTION SECTION:
;; 2a5630ac-12ac-46fa-b4c7-1fcdddfc2f8b.host.   IN      A

;; Received 59 B
;; Time 2023-09-09 02:07:32 CEST
;; From 127.0.0.1@53(UDP) in 0.3 ms


Which is. Probably not right?

Asking for SOA explicitly works:
$ dig soa $uuid.host
;; ->>HEADER<<- opcode: QUERY; status: NXDOMAIN; id: 20830
;; Flags: qr rd ra; QUERY: 1; ANSWER: 0; AUTHORITY: 1; ADDITIONAL: 0

;; QUESTION SECTION:
;; 2a5630ac-12ac-46fa-b4c7-1fcdddfc2f8b.host.   IN      SOA

;; AUTHORITY SECTION:
host.                   3581    IN      SOA     ns0.centralnic.net.
hostmaster.centralnic.net. 3000457776 900 1800 6048000 3600

;; Received 124 B
;; Time 2023-09-09 02:07:46 CEST
;; From 127.0.0.1@53(UDP) in 26.5 ms


And unbound behaves correctly here:

$ dig -p 5353 a $uuid.host
;; ->>HEADER<<- opcode: QUERY; status: NXDOMAIN; id: 33325
;; Flags: qr rd ra; QUERY: 1; ANSWER: 0; AUTHORITY: 1; ADDITIONAL: 0

;; QUESTION SECTION:
;; 2a5630ac-12ac-46fa-b4c7-1fcdddfc2f8b.host.   IN      A

;; AUTHORITY SECTION:
host.                   3462    IN      SOA     ns0.centralnic.net.
hostmaster.centralnic.net. 3000457776 900 1800 6048000 3600

;; Received 124 B
;; Time 2023-09-09 02:09:45 CEST
;; From 127.0.0.1@5353(UDP) in 0.3 ms
$ dig -p 5353 a $uuid.host
;; ->>HEADER<<- opcode: QUERY; status: NXDOMAIN; id: 11425
;; Flags: qr rd ra; QUERY: 1; ANSWER: 0; AUTHORITY: 1; ADDITIONAL: 0

;; QUESTION SECTION:
;; 2a5630ac-12ac-46fa-b4c7-1fcdddfc2f8b.host.   IN      A

;; AUTHORITY SECTION:
host.                   3462    IN      SOA     ns0.centralnic.net.
hostmaster.centralnic.net. 3000457776 900 1800 6048000 3600

;; Received 124 B
;; Time 2023-09-09 02:09:45 CEST
;; From 127.0.0.1@5353(UDP) in 0.3 ms
$ dig -p 5353 soa $uuid.host
;; ->>HEADER<<- opcode: QUERY; status: NXDOMAIN; id: 47525
;; Flags: qr rd ra; QUERY: 1; ANSWER: 0; AUTHORITY: 1; ADDITIONAL: 0

;; QUESTION SECTION:
;; 2a5630ac-12ac-46fa-b4c7-1fcdddfc2f8b.host.   IN      SOA

;; AUTHORITY SECTION:
host.                   3458    IN      SOA     ns0.centralnic.net.
hostmaster.centralnic.net. 3000457776 900 1800 6048000 3600

;; Received 124 B
;; Time 2023-09-09 02:09:49 CEST
;; From 127.0.0.1@5353(UDP) in 0.4 ms


So this is a............. dnsmasq cache-hit thing?

Best,
наб