Back in my day, sonny…there was a time when you could make your networking work without the network manager applet. Not that I’m saying the NetworkManager program is bad, because it actually has been getting better. But the fact of the matter is that I’m a networking guy and a server guy, so I need keep my config-file wits sharp. So take out your pocket knife and let’s start to whittle.
Begin by learning and making some notes about your interfaces before you start to turn off NetworkManager. You’ll need to write down these 3 things:
1) Your SSID and passphrase.
2) The names of your Ethernet and radio devices. They might look like wlan0, wifi0, eth0 or enp2p1.
3) Your gateway IP address.
Next, we’ll start to monkey around in the command line… I’ll do this with Ubuntu in mind. (Read the rest at Freedom Penguin)