DNS issue only in kubernetes on a windows host

[juchom]

First, here is some context, I have a domain for local dev with this records :

@                  A    127.0.0.1
*                  A    127.0.0.1
_acme-challenge   TXT   xxxxxxxxxxxxxxxxxxxxx

This issue is only happening on windows 11 (maybe 10 ?), there is no problem on Linux and MacOS.

Now if run this dns query from windows I have this result which is the expected one according to the zone :

dig cname _acme-challenge.linoa.dev.

; <<>> DiG 9.18.1-1ubuntu1.2-Ubuntu <<>> cname _acme-challenge.linoa.dev.
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30141
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1472
;; QUESTION SECTION:
;_acme-challenge.linoa.dev.     IN      CNAME

;; AUTHORITY SECTION:
linoa.dev.              78      IN      SOA     desi.ns.cloudflare.com. dns.cloudflare.com. 2304297281 10000 2400 604800 3600

;; Query time: 0 msec
;; SERVER: 172.28.208.1#53(172.28.208.1) (UDP)
;; WHEN: Tue Mar 14 18:02:22 CET 2023
;; MSG SIZE  rcvd: 116

Now if I run the same query from a pod inside the kubernetes cluster I have this result, with a CNAME pointing to itselft coming from nowhere.

dig cname _acme-challenge.linoa.dev.

; <<>> DiG 9.9.5-9+deb8u19-Debian <<>> cname _acme-challenge.linoa.dev.
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34937
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;_acme-challenge.linoa.dev.     IN      CNAME

;; ANSWER SECTION:
_acme-challenge.linoa.dev. 5    IN      CNAME   _acme-challenge.linoa.dev.

;; Query time: 3 msec
;; SERVER: 10.96.0.10#53(10.96.0.10)
;; WHEN: Tue Mar 14 17:01:

When the request is sent from the pod and we analyse the response in windows with wireshark the dns response is correct and then when we analyse the response with tcpdump inside the kubernetes cluster there is this CNAME appearing.

Expected behavior

This dns query is supposed to have the same behaviour on windows, linux and macos.

Here is my machine information :

Version WSL : 1.2.1.0
Version du noyau : 5.15.90.1
Version WSLg : 1.0.51
Version MSRDC : 1.2.3770
Version direct3D : 1.608.2-61064218
Version de DXCore : 10.0.25131.1002-220531-1700.rs-onecore-base2-hyp
Version de Windows : 10.0.22621.1555

I tried with Docker for Windows v4.18 (with WSL2 and Hyper-V backend) and minikube.

Steps to reproduce the behavior

• Install Docker for dekstop latest release
• Enable kubernetes
• kubectl run tmp-shell --rm -i --tty --image nicolaka/netshoot
• dig _acme-challenge.linoa.dev. CNAME