Documentation › Connected Clients

Connected Clients

The Connected Clients page gives you a real-time view of every MQTT client currently connected to your broker. Monitor active sessions, identify unexpected connections, and take immediate action by enabling or disabling clients on the fly.

What It Shows

The Connected Clients page displays a live list of all MQTT sessions currently open on the broker. Each row represents one active connection:

  • Client ID - the MQTT client identifier provided during connection
  • Username - the username used to authenticate
  • IP Address - the remote IP address of the connected device
  • Protocol Version - MQTT protocol version in use (3.1, 3.1.1, or 5.0)
  • Connected Since - timestamp showing when the connection was established
  • Keep Alive - the keep-alive interval negotiated with the client, in seconds
  • Clean Session - whether the client connected with a clean session flag

The table refreshes automatically to reflect newly connected and disconnected clients.

Auto-Refresh Behavior

The page polls the broker at regular intervals to keep the client list current. No manual refresh is needed. New connections appear within a few seconds of the client connecting. Clients that disconnect are removed from the list on the next refresh cycle.

Disabling a Client

Disabling a client from this page takes effect immediately and performs two actions:

  1. The client is kicked from the broker - its current connection is terminated.
  2. The client is blocked from reconnecting until you re-enable it. Any reconnection attempts are rejected by the broker.

To disable a client, locate it in the table and click the toggle or disable button next to it. The broker immediately closes that client's connection.

Enabling a Client

If a client has been previously disabled, find it in the list and click the enable toggle. The client's status changes to enabled immediately and it can connect normally again.

What Happens When a Client Is Disabled

  • The broker terminates the TCP/MQTT connection immediately.
  • If the client has clean_session=false, its queued messages are held but not delivered while disabled.
  • Reconnection attempts are rejected with an authorization error.
  • The client remains in your ACL client list but is flagged as disabled.
  • Re-enabling the client allows it to reconnect normally.

Connected Clients vs ACL Clients

These are two different views serving different purposes:

  • Connected Clients - shows only clients currently connected, with real-time session data (IP, protocol, uptime). Changes take effect on live connections.
  • ACL Clients - shows all configured MQTT client accounts whether online or not. Used for account management (credentials, roles, groups).

Think of ACL Clients as your user account database, and Connected Clients as the live session monitor.

Use Cases for Disabling Clients

  • Security incident - a device has been compromised or is sending unexpected traffic. Disable it immediately without needing to change passwords or delete the account.
  • Maintenance - a device needs to go offline for firmware update or physical work. Disable it in BunkerM so queued messages do not accumulate.
  • Testing - test how your system behaves when a specific client goes offline without physically disconnecting the device.
  • Suspicious activity - a client is connecting from an unexpected IP address or at unusual hours. Disable it while you investigate.
Note: Disabling a client from the Connected Clients page is equivalent to disabling it from the ACL Clients page. Both update the same underlying state in Mosquitto's dynamic security. If a client has multiple simultaneous connections, disabling it closes all of them.
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