Linux network nightmare
How to configure network
At the beginning there was Redhat, with... I don't remember.
Then, there was interfaces. /etc/network/interfaces . Just one file, good.
To configure static ip address:
auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 10.91.40.20 netmask 255.255.0.0 network 10.91.0.0 gateway 10.91.50.1 broadcast 10.91.255.255
In the new versions, this must be activated, unactivating eth0 for NetworkManager. In /etc/NetworkManager/NetworkManager.conf, set:
[main] plugins=ifupdown,keyfile
[ifupdown] managed=false
[device] wifi.scan-rand-mac-address=no
and then edit interfaces.
Test it with a reboot!
Wi-Fi
For testing, if NetworkManager is enabled, you can use nmcli (and comment eth0 in interfaces):
nmcli device wifi connect Benediktinai password Daukanto21
It won't restart at boot!
Test
ping www.google.com
(it's reachable by now, 18/12/2021).