nix-config/machines/aramis/networking.nix

{ ... }:
{
  networking = {
    hostName = "aramis";

    # The global useDHCP flag is deprecated, therefore explicitly set to false here.
    # Per-interface useDHCP will be mandatory in the future, so this generated config
    # replicates the default behaviour.
    useDHCP = false;

    interfaces = {
      enp0s31f6.useDHCP = true;
      wlp0s20f3.useDHCP = true;
    };
  };

  my.hardware.networking = {
    # Which interface is used to connect to the internet
    externalInterface = "enp0s3";

    # Enable WiFi integration
    wireless.enable = true;
  };
}