nixos-config/machines/massicot/networking.nix

{ pkgs, ... }: {
  networking = {
    interfaces = {
      eth0.useDHCP = true;
      eth0.ipv6.addresses = [{
        address = "2a01:4f8:c17:345f::1";
        prefixLength = 64;
      }];
    };
    defaultGateway6 = {
      address = "fe80::1";
      interface = "eth0";
    };
    nameservers = [ ];
  };
}