sudo airmon-ng start wlan0 sudo airodump-ng wlan0mon | Problem | Solution | |----------------------------------|-----------------------------------------------| | No interface shown in iwconfig | Plug in a compatible USB Wi-Fi adapter | | Interface exists but Fern fails | Run sudo airmon-ng check kill + manual monitor mode | | Still not working | Use Wifite or aircrack-ng instead of Fern | | Internal card only | Buy a supported external adapter (~$20–40) | Final Note Fern WiFi Cracker is old and less maintained. Many modern Kali users skip it in favor of Wifite (simpler) or aircrack-ng (more control). If you’re learning Wi-Fi penetration testing, focus on those instead.
sudo airmon-ng check kill This kills processes like NetworkManager , wpa_supplicant , etc. Kali Linux Fern Wifi Cracker No Wireless Interface Was Found
iwconfig Or:
sudo systemctl restart NetworkManager Sometimes Fern fails to switch the card to monitor mode automatically. Do it manually: sudo airmon-ng start wlan0 sudo airodump-ng wlan0mon |