{
  networking.firewall.enable = true;

  security.sudo.execWheelOnly = true;

  security.sudo.wheelNeedsPassword = true;

  security.audit.enable = true;

  services = {
    openssh = {
      enable = true;
      settings.PermitRootLogin = "no"; # distributed-build.nix requires it
      settings.PasswordAuthentication = false;
      allowSFTP = false;
    };
    fail2ban = {
      enable = true;
    };
  };
  nix.settings.allowed-users = ["root" "@users"];
}
