Where is the network interface settings file stored in debian?

Question

linux

Hello. Recently put some network cards on the computer. I admit, for some time I puzzled over how to launch and configure them using the "ethtool" utility. Now it has "grown" to the point that I think where to prescribe some commands / scripts so that the cards are turned on and configured during system boot. About subdirectories in /etc, I think everything is traditionally done there, in particular, /etc/network/intefaces determines the entire routing assignment of poppy-ip addresses, but I think there is some other file associated specifically with the hardware settings of the card itself and the command syntax seems different. Tell me please!? Where to dig?

Answer 1

see also /etc/network/intefaces.d includes