Nut server unreachable from UGREEN

Hardware and upgrades
1

Hello,

I would like to report several technical issues regarding the NUT (Network UPS Tools) implementation in UGREEN OS.

  1. upsd only listens on the loopback interface.
    The daemon is bound exclusively to 127.0.0.1:3493, which prevents any external NUT client (Home Assistant, a Raspberry Pi, Linux servers, Synology, etc.) from connecting.
    A proper NUT server must be able to listen on the LAN interface so that other devices can retrieve UPS status.

  2. The protocol exposed on port 3493 is not NUT-compliant.
    Even when a remote device tries to connect, the NAS does not respond to standard NUT commands.

    • The initial handshake is not accepted

    • NUT commands like LOGIN, LIST UPS, GET VAR, etc., are rejected

    • The connection is immediately closed
      This means the service is not interoperable with any existing NUT clients.

  3. The “NUT Server” option in the UI is misleading.
    The label suggests that the NAS acts as a standard NUT server over the network.
    In reality, it appears to work only between UGREEN devices using a private, undocumented protocol that is different from NUT.

  4. Result: the UPS cannot be integrated into any external system.
    Because the NAS does not implement a real NUT server, it is currently impossible to:

    • monitor UPS status from Home Assistant

    • use the NAS as a network UPS for other devices

    • integrate with Linux servers, Synology, Proxmox, etc.
      This forces users to plug the UPS directly into each device, which is not always possible and defeats the purpose of network UPS support.

Expected Behavior / Recommendation

UGREEN OS would benefit greatly from true NUT compatibility. Specifically:

  • upsd should be able to listen on a LAN IP address

  • The protocol should follow the official NUT specifications

  • A clear “Standard NUT Server” mode should be offered (in addition to any internal UGREEN protocol)

  • Documentation of the UPS API and network behavior would help power users and integrators

These features are already implemented by other NAS vendors (Synology, QNAP) and by standard Linux distributions, and they dramatically improve integration in multi-device environments.

I can provide tcpdump traces or logs showing the current behavior if needed.

Thank you.

2

Try contacting Ugreen’s technical support, this is an unofficial forum, in case you didn’t notice.

1 Like