DNS SRV record queries fail with NOTIMP after upgrading client to 0.74.x / 0.75.0 (regression from 0.73.2)

[minhduy1302]

Before posting

• I searched existing discussions and issues, including closed ones, and checked the relevant docs.
• I believe this is a product bug rather than a configuration or setup question.
• I can reproduce this issue, or for intermittent issues I've included trigger, frequency, and timing details below.
• I removed or anonymized sensitive data from logs, screenshots, and configuration.

Affected area

Client / Agent, DNS

Deployment type

Self-hosted - quickstart script

Operating system or environment

Windows

NetBird version and upgrade status

Netbird Client: 0.74.x and 0.75.0

Did this work before?

Yes, this worked before

Regression details

• Last known working version: 0.73.2
• First known broken version: 0.74.1

Summary

Since upgrading the NetBird client to 0.74.x or 0.75.0, DNS SRV record lookups through the NetBird DNS resolver fail with a NOTIMP (Not Implemented) error. This breaks connections to services that rely on SRV-based discovery, such as MongoDB Atlas mongodb+srv:// connection strings.
Downgrading the client back to 0.73.2 immediately resolves the issue, with no other configuration changes.

Current behavior

$ nslookup -type=SRV _mongodb._tcp.my-cluster.hbltto.mongodb.net
;; Got recursion not available from 10.255.255.254
Server:         10.255.255.254
Address:        10.255.255.254#53

** server can't find _mongodb._tcp.my-cluster.hbltto.mongodb.net: NOTIMP

Expected behavior

The SRV query should be resolved/forwarded normally, as it was on client version 0.73.2, returning the expected SRV records instead of a NOTIMP error.

$ nslookup -type=SRV _mongodb._tcp.my-cluster.hbltto.mongodb.net
Server:         10.255.255.254
Address:        10.255.255.254#53

Non-authoritative answer:
_mongodb._tcp.my-cluster.hbltto.mongodb.net  service = 0 0 27017 my-cluster-shard-00-00.hbltto.mongodb.net.
_mongodb._tcp.my-cluster.hbltto.mongodb.net  service = 0 0 27017 my-cluster-shard-00-01.hbltto.mongodb.net.
_mongodb._tcp.my-cluster.hbltto.mongodb.net  service = 0 0 27017 my-cluster-shard-00-02.hbltto.mongodb.net.

Authoritative answers can be found from:

Steps to reproduce

1. Install the NetBird client
2. Log in / connect to the self-hosted NetBird
3. Once connected, run an SRV lookup against any external domain that requires one
4. Observe the query fails with NOTIMP, even though this is a plain internet domain, not something served by any NetBird DNS route
5. Disconnect, downgrade the client to 0.73.2 only (management server unchanged), reconnect, repeat step 3 — the SRV query now resolves correctly

Environment and topology

• NetBird client version (broken): 0.74.x, 0.75.0
• NetBird client version (working): 0.73.2
• Self-hosted NetBird management server version: any version.
• OS / architecture: Windows 11 x64
• NetBird managed DNS enabled: yes

Self-hosted details, if available

• Deployment method: Docker Compose
• Netbird Server: 0.73.2, 0.74.7, 0.75.0
• Dashboard: 2.90.7

Logs, status output, or debug evidence

N/A

Related issues or discussions

No response

Impact

No response

Additional context

No response

[lixmal]

Try upgrading the routing peer to v0.74.x first. The behavior on the client changed a little to avoid dns cache poisoning on upstream handlers on the client.

[minhduy1302]

Thank you!
Upgrading the routing peer to v0.74.x resolved the issue.