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Wi-Fi

Wifi Network not appearing in Ubuntu [HP]
Solution
sudo apt-get install bcmwl-kernel-source

Command to check network driver installed on your system

lspci | grep Network

WiFi not working in HP laptop RTL8723DE Realtek wireless driver

This method is exclusively for RTL8723DE series of wireless adapters. So make sure that you have these adapters by using this command:
sudo lshw -C network
If you see a wireless network adapter starting with RTL, then only you should go ahead
sudo apt update
sudo apt install git dkms
git clone https://github.com/smlinux/rtl8723de.git -b 4.11-up
sudo dkms add ./rtl8723de
sudo dkms install rtl8723de/5.1.1.8_21285.20171026_COEX20170111-1414
sudo depmod -a
Reboot
📶
and your wireless should be working.
😀
OR TRY THIS
recommend for HP users facing WiFi problem
sudo apt-get install linux-headers-$(uname -r) build-essential git
git clone https://github.com/lwfinger/rtlwifi_new.git
cd rtlwifi_new/ && git checkout origin/extended -b extended
sudo make install
sudo modprobe -r rtl8723de
sudo modprobe rtl8723de
sudo apt purge bcmwl-kernel-source
sudo sed -i '/blacklist bcma/ d' /etc/modprobe.d/blacklist.conf
sudo sed -i '/blacklist brcmsmac/ d' /etc/modprobe.d/blacklist.conf
sudo modprobe -r rtl8723de && sleep 5 && sudo modprobe rtl8723de ant_sel=1
sudo modprobe -r rtl8723de && sleep 5 && sudo modprobe rtl8723de ant_sel=2
echo "options rtl8723de ant_sel=X" | sudo tee /etc/modprobe.d/rtl8723de.conf
📶
Reboot your PC.

Fix no WiFi in Ubuntu with Broadcom wireless adapters

This method is exclusively for Broadcom 43 series of wireless adapters. So make sure that you have these adapters by using this command:
sudo lshw -C network
If you see a wireless network adapter starting with BCM43, then only you should go ahead .
sudo apt remove broadcom-sta-dkms bcmwl-kernel-source
sudo apt install firmware-b43-installer
Once the install is finished doing its work, you’ll need to reboot. After you log back in, you’ll be able to see and access your wifi connections.

Ubuntu WiFi is disabled

Simply putting it on suspend and bringing it back up seems to make the wifi work normally.This is not a permanent solution.The only problem is to do this every time start Ubuntu.
just want to reactivate your WiFi
rfkill command used to enable/disable network drivers or activate or deactivate Network Adapters
sudo rfkill unblock wifi