QNAP TS-233 disappears from LAN after ~2 minutes, but remains accessible via Tailscale
Update:
I found the root cause of the issue.
The problem was caused by the installed Tailscale application (the official one from qnap app store).
When I stopped the Tailscale service, the NAS immediately became reachable again over the local LAN and everything worked normally.
As soon as I started the Tailscale service again, the NAS disappeared from the local network with the exact same behavior as before, while it remained accessible through Tailscale.
To test this, I removed the existing Tailscale installation and installed the latest version from the MyQNAP repository. After upgrading to the newer version, the problem disappeared completely. The NAS is now fully accessible over both the local LAN and Tailscale, even after reboots.
As an additional suggestion, if someone from QNAP is reading this, I would recommend updating the Tailscale package available through the official QNAP App Center. The version currently provided there appears to be several years out of date, which can lead to compatibility issues and makes troubleshooting much more difficult.
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I’m completely stuck and hoping someone has seen this before.
My TS-233 worked perfectly until I updated QTS. Since the update, the NAS boots normally and is fully accessible via its LAN IP for about 2 minutes. Then it suddenly disappears from the local network.
Symptoms:
LAN IP stops responding.
NAS disappears from the router’s client list.
Qfinder can no longer find it.
SMB/Web UI/SSH over LAN all stop working.
The strange part is that the NAS is still online:
Tailscale continues to work perfectly.
I can SSH into it through Tailscale.
From the NAS, I can ping my router and other LAN devices.
ip addr, ip route, and the interface all look normal.
Link stays up at 1 Gbps.
Things I’ve already tried:
Downgraded to the previous firmware.
Downgraded again to the firmware version that was running before the issue started.
Switched between static IP and DHCP.
Removed DHCP reservation.
Restarted the network service.
Disabled QuFirewall completely.
Performed the 3-second reset (network settings reset).
The 3-second reset temporarily restored LAN access. The NAS received a fresh DHCP address, worked for about 2 minutes, and then disappeared from the LAN again with exactly the same behavior while remaining fully accessible through Tailscale.
At this point I’m wondering if the firmware update corrupted some internal networking component that survives firmware downgrades, or if there’s another service killing LAN connectivity after boot.
Has anyone experienced anything similar or found a fix? Any ideas would be greatly appreciated.