DNS responses are not used by the system but nslookup works

Question

I am setting up a Windows computer. It is a rather strange setup, but it is necessary my company's workflows developed on Linux will also work here. I will add background information to the end. But first the facts.

• I have an Ubuntu System set up in Windows 10 with WSL2.
• The Ubuntu System is a gateway to a local subnet.
• Inside the local subnet I have a private DNS server running.
  • This DNS Server has 8.8.8.8 as a fallback server, if it doesn't know the answer
  • It is the only DNS Server set in Windows, no other DNS servers are there
• When I open PowerShell and nslookup a domain — either in the www or the local subnet — I receive the correct response. (Windows)
• When I ping the domain or open it in a web browser it cannot look it up. This if for both public and private domains (Windows)
• When I ping the IP address returned from nslookup or open it works perfectly fine (Windows)
• When I ping dnsdock and it works (Ubuntu WSL2)

All the responses are non-authorative, which makes perfect sense, since it's forwarded through a private DNS server. Is Windows ignoring non-authorative answers?

Background

I think that describes my problem, but I think it's inevitable that I will get comments asking why my setup is that complicated. It's a computer for one of our developers. We are developing within Docker and inside Ubuntu Docker is installed natively (not via Docker desktop) because that allowed for forwarding to the actual containers.

I can ping them. To do so, I had to set up Ubuntu as a router (IPv4 forwarding to active and IP Table rules for forwarding). I also had to write a PowerShell script that reset the route on login because the IP address of Ubuntu changes on every startup. The private DNS server is DNSDock. It connects to the Docker socket and reads out Docker container automatically. It will a container’s name or tag or environment argument to a domain name.

This allows for DNS resolution of Docker containers and removes the need to bind ports. Which means that we can have as many parallel containers running as we want without adjusting the ports. Quite neat for multiple projects or micro services!

Don’t forget that they have to communicate with each other more often than not. It is important that a developer can just go into the project and run docker-compose up. The whole idea is that the operating system doesn’t matter and no completely new methods have to be developed for people using Windows.

Here is the nslookup output for reference:

PS C:\WINDOWS\system32> nslookup www.yahoo.com 172.17.0.1
Server:  UnKnown
Address:  172.17.0.1

Non-authoritative answer:
Name:    new-fp-shed.wg1.b.yahoo.com
Addresses:  2a00:1288:110:c305::1:8000
          2a00:1288:110:c305::1:8001
          87.248.100.215
          87.248.100.216
Aliases:  www.yahoo.com

PS C:\WINDOWS\system32> nslookup www.yahoo.com
Server:  UnKnown
Address:  172.17.0.1

Non-authoritative answer:
Name:    new-fp-shed.wg1.b.yahoo.com
Addresses:  2a00:1288:110:c305::1:8000
          2a00:1288:110:c305::1:8001
          87.248.100.216
          87.248.100.215
Aliases:  www.yahoo.com

And here is the docker-compose file that starts and controls the DNS server:

version: '3.7'
services:
  dnsdock:
    image: aacebedo/dnsdock:v1.16.4-amd64
    network_mode: bridge
    restart: unless-stopped
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    container_name: dnsdock
    ports:
      - 172.17.0.1:53:53/udp
      #- 53:53/udp
    environment:
      - nameserver="8.8.8.8:53"

/etc/resolv.conf

 nameserver 172.17.0.1

ipconfig printout

PS C:\Users\<redacted>> ipconfig /all

Windows IP Configuration

   Host Name . . . . . . . . . . . . : <redacted>
   Primary Dns Suffix  . . . . . . . :
   Node Type . . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No

Wireless LAN adapter LAN-Verbindung* 1:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft Wi-Fi Direct Virtual Adapter
   Physical Address. . . . . . . . . : <redacted>
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes

Wireless LAN adapter WLAN:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Marvell AVASTAR Wireless-AC Network Controller
   Physical Address. . . . . . . . . : <redacted>
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 192.168.0.191(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : Thursday, January 14, 2021 7:07:52 AM
   Lease Expires . . . . . . . . . . : Thursday, January 14, 2021 8:07:50 AM
   Default Gateway . . . . . . . . . : 192.168.0.1
   DHCP Server . . . . . . . . . . . : 192.168.0.1
   DNS Servers . . . . . . . . . . . : 172.17.0.1
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Bluetooth-Netzwerkverbindung:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Bluetooth Device (Personal Area Network)
   Physical Address. . . . . . . . . : <redacted>
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes

Ethernet adapter vEthernet (WSL):

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Hyper-V Virtual Ethernet Adapter
   Physical Address. . . . . . . . . : <redacted>
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 172.18.9.65(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.240
   Default Gateway . . . . . . . . . :
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter vEthernet (Default Switch):

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Hyper-V Virtual Ethernet Adapter #2
   Physical Address. . . . . . . . . : <redacted>
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 172.18.63.65(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.240
   Default Gateway . . . . . . . . . :
   NetBIOS over Tcpip. . . . . . . . : Enabled

Answer 1

Add the DNS server to your other 2 "NICs". The priority of your NICs might be causing one of those adapters to return a doesn't exist error on the DNS lookup because they don't have DNS servers set according to your ipconfig /all. You could probably still fix it without doing this by adjusting your routing metrics or interface indexes in windows but that gets complicated.