What is the WPA Supplicant Service?
In Ubuntu (and almost all Linux distributions), wpa_supplicant is the core background daemon responsible for handling wireless network authentication (like WPA2 and WPA3 passwords). It is the software that allows your computer to negotiate a secure connection with a Wi-Fi router.
If you are running a desktop PC that does not even have a Wi-Fi card, or if you are running a home server that is permanently hardwired via an Ethernet cable, this service is completely useless. Despite this, it still runs in the background, consuming a tiny amount of RAM and occasionally logging unnecessary events. For a strictly wired machine, it is good practice to disable it entirely to keep the system as lightweight as possible.
How to Stop WPA Supplicant in Ubuntu
To prevent the service from running, you must disable it using systemctl.
- Open your Ubuntu Terminal (shortcut:
Ctrl + Alt + T). - First, check if the service is currently running on your machine:
systemctl status wpa_supplicant.service- Stop the service for the current session by running:
sudo systemctl stop wpa_supplicant.service- Disable the service so it does not launch on the next reboot:
sudo systemctl disable wpa_supplicant.service- (Optional but Recommended): If you want to absolutely guarantee that NetworkManager or another script does not accidentally wake the service up via D-Bus, you should mask it:
sudo systemctl mask wpa_supplicant.serviceYour Ethernet connection will continue to work perfectly, as wired connections are handled directly by the kernel and NetworkManager, completely bypassing the need for wireless authentication protocols.