Ubuntu runs ifconfig and can connect to the Internet, but the network configuration cannot be found.

 1. Run ifconfig on the terminal and cannot find it.

 Here, the front-end lock cannot be obtained. The solution is to restart ubuntu.

2. sudo is the super user, and the terminal runs sudo apt install net-tools

 3. Check the network configuration

You can see that the wired network port is ens33

 4. Enable or disable the network

sudo ifconfig ens33 up

sudo ifconfig ens33 down

 practise: