The Aggressive Reconnect
Like most modern operating systems, Ubuntu remembers the passwords for Wi-Fi networks you have successfully joined in the past. By default, it configures these saved profiles to “Connect automatically.” Whenever your computer detects that a known network is within range, it will drop its current connection and attempt to join the saved one. This is problematic if you have saved the credentials for a public library or coffee shop network, and you live or work nearby. Ubuntu will constantly try to automatically reconnect to the weak public signal, dropping your secure mobile hotspot or disrupting your active connection.
Managing the Network Profile
To ensure your network remains stable and stop Ubuntu from automatically reconnecting to previously saved Wi-Fi networks, you must modify the specific connection profile in your network settings.
Click the network icon in the top right corner of your screen (in the system tray) to open the quick settings menu. Click the small arrow next to your active Wi-Fi connection and select Wi-Fi Settings. This opens the main Network settings panel. Under the “Visible Networks” or “Known Networks” section, locate the specific Wi-Fi network you want to restrict. Click the gear icon next to it to open its properties. In the new window, ensure you are on the Details tab. Look for the toggle switch explicitly labelled Connect automatically. Click this toggle so it turns Off. Click Apply (or close the window, depending on your Ubuntu version). The password remains saved for manual connections, but Ubuntu will no longer try to join it without your explicit instruction.