Debian network interface goes to sleep, how to disable power saving?

Question

Debian

Hello everyone
Installed Debian 10.3 on a spinner with no desktop environment. Everything works fine, but after a while of non-use of the system, the network interface falls off. The machine does not respond. It is worth going to the machine to ping some host, for a while the system will think then it starts to ping, after that Debian pings and works fine
Which way to dig?

Answer 1

1. Disable iptables
2. Change the network interface in the virtual machine.
What virtual machine