[NEBULA] Switch becomes unreachable after configuration with management VLAN and using DHCP

VanWerven Posts: 9
edited April 2021 in Nebula


We are using an other default management VLAN and this is giving us problems when configuring switches.

The default VLAN is 1800, and this is set up under the site settings. The switches are configured with the uplink port on PVID 1800 and the IP is set through DHCP.

When the switch boots for the first time, it picks up the configuration, but becomes unresponsive after a few minutes.

When however we are setting up an static IP on the interface it seems to be working normally.

All Replies

  • Additionally, we also need to manually set the management VLAN. It looks like it doesn't set up the management vlan automatically when setting the IP.

  • RUnglaube
    RUnglaube Posts: 135  Ally Member

    Did you manage to solve it? You indeed need to set the correct management VLAN, either per device or globally and also configure the uplink port with the correct PVID.

    "You will never walk along"
  • We did solve it, but we have to set the management VLAN manually although the management VLAN is set site wide. Looks like an bug to me.

  • Zyxel_Jason
    Zyxel_Jason Posts: 371  Master Member

    Hi @VanWerven ,

    To change management VLAN and PVID of uplink on Nebula Switch on NCC, you will need to change the management VLAN on NCC first(either global setting or per device setting), then go to configure PVID of uplink port.

    Please note that if you configure PVID of uplink first, it may cause Switch disconnect from NCC because it loses connection from the Internet.

    Hope it helps.

  • Hi Jason,

    The management vlan is set in NNC but only globally, (see screenshot below) the rest of the settings are already in place on the switch. When the device configures it becomes unresponsive after a few minutes.

    We've found out that this isn't the case when we are setting the same VLAN manually on the management of the switch.

    So it seems to be an issue when it isn't set manually.

  • Zyxel_Jason
    Zyxel_Jason Posts: 371  Master Member

    Hi @VanWerven ,

    If you configure PVID on the Switch's uplink first, it will make Switch disconnect from the Internet.

    Then you will find that it is not working when you try to configure management VLAN because Switch is already disconnected from Nebula CC.

    That is why you need to access the Switch via WebGUI and configure management VLAN manually to let Switch back online.

    Hope it helps.

  • Hi Jason, thanks for the reply.

    We are not doing things first or last because we are setting up the device using the Nebula CC and are connecting the switch afterwards. so it should fetch the config and configure itself automatically.

    Now we are just configuring the management VLAN manual for each device instead of through the global configuration and that is going fine.

  • Zyxel_Jason
    Zyxel_Jason Posts: 371  Master Member

    Hi @VanWerven ,

    I would like to clarify the behavior of applying configuration from NCC.

    If the user pre-configure the Nebula device on NCC(Configure settings before the device is online on NCC) or the Nebula device is offline, the configuration status will be "not up to date" and new configuration will be in the queue on NCC. It will follow FIFO to push new configuration to the device when the device gets online.

    In you case, the flow and procedure will be like:

    1. Register Nebula Switch and add it to a site on NCC.
    2. Pre-configure management VLAN in SWITCH -> Configure -> Switch configuration.
    3. Pre-configure PVID for uplink port in SWITCH -> Configure -> Switch ports.
    4. Power on Nebula Switch and connect it to the Internet.(It will use VLAN 1 as management VLAN, uplink port is PVID 1, untagged out by default.)
    5. NCC will push new management VLAN to Switch.(The Switch might offline because new management VLAN is tagged out on uplink port, it will back to use VLAN 1 to connect NCC again.)
    6. NCC will push new PVID for uplink port to Switch. Since the Switch will still try to use new management VLAN every 30 seconds in the background and now PVID is correct, the Switch should be online with new management VLAN and correct PVID.

    Hope it helps.


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