Network does not include all of the aliased domains

[gpechiro]

Actual Behavior

When requesting a CNAME for a domain inside a container the IP is resolved properly but it does not include the domain the CNAME alias is for, the A record.

Steps to Reproduce

Start an ubuntu docker container docker run --rm -it --entrypoint /bin/bash ubuntu
Install dnsutils apt update && apt install -y dnsutils
Run nslookup on a url with a CNAME nslookup test.xiphoid24.com

Result

The proper IP address is resolved but the CNAME is returned as the Name and not an alias. The actual name (loc.xiphoid24.com) is not returned.

# nslookup test.xiphoid24.com
Server:         172.30.59.98
Address:        172.30.59.98#53

Non-authoritative answer:
Name:   test.xiphoid24.com
Address: 127.0.0.1

Expected Behavior

The proper IP address is resolved, the A record is listed as the name and the CNAME is listed as an Alias.

Address:  192.168.1.1

Non-authoritative answer:
Name:    loc.xiphoid24.com
Address:  127.0.0.1
Aliases:  test.xiphoid24.com

Additional Information

No response

Rancher Desktop Version

1.9.1

Rancher Desktop K8s Version

N/A

Which container engine are you using?

moby (docker cli)

What operating system are you using?

Windows

Operating System / Build Version

Windows 10 Pro 22H2

What CPU architecture are you using?

x64

Linux only: what package format did you use to install Rancher Desktop?

None

Windows User Only

No

[gunamata]

I could reproduce the behavior stated in the issue description. Also, when I directly run the command in Powershell on the host machine, I see the actual name (loc.xiphoid24.com) printed in the output.

@Nino-K , Do you have any quick insights on what could be the reason nslookup command doesn't show the actual name from within a container?

In Powershell

> nslookup test.xiphoid24.com
Server:  UnKnown
Address:  fe80::d635:1dff:fead:319a

Non-authoritative answer:
Name:    loc.xiphoid24.com
Address:  127.0.0.1
Aliases:  test.xiphoid24.com
 

[jandubois]

This looks like a bug in the Rancher Desktop host resolver.

Could you check if the bug is fixed by enabling the experimental network tunnel feature (see https://docs.rancherdesktop.io/ui/preferences/wsl/network), as that bypasses the host resolver?

[gpechiro]

@jandubois I enabled the experimental network tunnel and I am getting the same results.

# nslookup test.xiphoid24.com
Server:         192.168.127.1
Address:        192.168.127.1#53

Non-authoritative answer:
Name:   test.xiphoid24.com
Address: 127.0.0.1

[Nino-K]

You have attached the output of the nslookup from Windows as an expected behavior. When you run the query you have attached on different platforms you'll get different output. I have also run the query on the Ubuntu distro and it looks like I get the correct output.

Windows

nslookup test.xiphoid24.com
Server:  pd2nsc5.st.vc.shawcable.net
Address:  2001:4e8:0:4009::15

Non-authoritative answer:
Name:    loc.xiphoid24.com
Address:  127.0.0.1
Aliases:  test.xiphoid24.com

MacOS

nslookup test.xiphoid24.com
Server:		2001:4e8:0:4009::15
Address:	2001:4e8:0:4009::15#53

Non-authoritative answer:
test.xiphoid24.com	canonical name = loc.xiphoid24.com.
Name:	loc.xiphoid24.com
Address: 127.0.0.1

Ubuntu Distro on Rancher Desktop

nslookup test.xiphoid24.com
Server:         172.27.176.1
Address:        172.27.176.1#53

Non-authoritative answer:
test.xiphoid24.com      canonical name = loc.xiphoid24.com.
Name:   loc.xiphoid24.com
Address: 127.0.0.1

Furthermore, different output from nslookup on different platforms is only related to the implementation of the nslookup itself on that specific platform.

I'm going to close this issue as it does not seem to be a real problem.