DNS server doesn't handle domain name capitalisation correctly

[tillnelown]

Describe the problem

When a DNS query uses random capitalisation like the one which is used to prevent cache poisoning Netbird will respond with NXDOMAIN.

To Reproduce

Steps to reproduce the behavior:

1. Connect to a Netbird network
2. Run a DNS query to the local resolver for a hostname
   dig @10.74.x.y <hostname>.<domain> works but dig @10.74.x.y <hOstName>.<dOmAin> does not
   dig @10.74.42.7 me.client.netbird works but dig @10.74.42.7 Me.Client.netbird does not

Expected behavior

Netbird should ignore these capitalisations as they are not relevant in this context.

Are you using NetBird Cloud?

I'm using the selfhosted instance though this seems like a client issue.

NetBird version

netbird version
0.27.10

[nazarewk]

@tillnelown can you check whether this is still not worknig for you with the latest NetBird version?

Seems like it works fine for me when using Network Resources:

kdn@brys ~> ssh anji-vm-macos-01 dig +short sElF.nb.test @100.83.255.254
192.168.100.10
kdn@brys ~> ssh anji-vm-macos-01 dig +short self.nb.test @100.83.255.254
192.168.100.10

[tillnelown]

@nazarewk I went back to a pure Wireguard mesh for now so I can't test it as the original setup doesn't exist anymore.
I'll try to migrate back to Netbird once a few other issues have been resolved, feel free to close this issue if you feel you've tested it enough and I'll open it again if i encounter it.

If anyone wants to replicate the exact setup:
I had a Netbird network that was connected to a wireguard mesh through routing, to better facilitate client communication I set up the Technitium DNS Server where the inside IPs of the peers where added. I wanted to point at Netbird as an upstream dns server to automatically get the Netbird client IPs to serve to the Wireguard clients but Technitium used DNS-0x20 encoding for upstream servers which Netbird didn't answer.