infra/nix/os/devices/sj-vps-htz0/system.nix

{
  pkgs,
  lib,
  config,
  repoFlake,
  ...
}: {
  networking.firewall.enable = true;
  networking.nftables.enable = true;

  networking.firewall.allowedTCPPorts = [
    # iperf3
    5201
  ];
  networking.firewall.logRefusedConnections = false;

  networking.usePredictableInterfaceNames = false;

  networking.dhcpcd.enable = false;

  networking.interfaces.eth0 = {
    mtu = 1400;
    useDHCP = false;
    ipv4.addresses = [
      {
        "address" = "167.233.1.14";
        "prefixLength" = 29;
      }
    ];
    ipv6.addresses = [];
  };

  networking.defaultGateway = {
    address = "167.233.1.9";
    interface = "eth0";
  };

  networking.defaultGateway6 = {
    address = "fe80::1";
    interface = "eth0";
  };

  networking.nameservers = ["1.1.1.1#one.one.one.one" "1.0.0.1#one.one.one.one"];

  services.resolved = {
    enable = true;
    dnssec = "true";
    domains = ["~."];
    fallbackDns = ["1.1.1.1#one.one.one.one" "1.0.0.1#one.one.one.one"];
    extraConfig = ''
      DNSOverTLS=yes
    '';
  };

  networking.nat = {
    enable = true;
    internalInterfaces = ["ve-*"];
    externalInterface = "eth0";
  };

  networking.firewall.filterForward = true;
  networking.firewall.extraForwardRules = ''
    meta nfproto ipv4 tcp flags syn tcp option maxseg size set 1360;
    meta nfproto ipv6 tcp flags syn tcp option maxseg size set 1340;
  '';

  # virtualization
  virtualisation = {docker.enable = false;};

  services.spice-vdagentd.enable = true;
  services.qemuGuest.enable = true;

  nix.gc = {automatic = true;};

  containers = {
    mailserver = import ../../containers/mailserver.nix {
      inherit repoFlake;

      autoStart = true;

      hostAddress = "192.168.100.10";
      localAddress = "192.168.100.11";

      imapsPort = 993;
      sievePort = 4190;
    };

    webserver =
      import ../../containers/webserver.nix
      {
        inherit repoFlake;

        autoStart = true;

        hostAddress = "192.168.100.12";
        localAddress = "192.168.100.13";

        httpPort = 80;
        httpsPort = 443;
      };

    syncthing = import ../../containers/syncthing.nix {
      autoStart = true;

      hostAddress = "192.168.100.14";
      localAddress = "192.168.100.15";

      syncthingPort = 22000;
    };
  };

  # This value determines the NixOS release from which the default
  # settings for stateful data, like file locations and database versions
  # on your system were taken. It‘s perfectly fine and recommended to leave
  # this value at the release version of the first install of this system.
  # Before changing this value read the documentation for this option
  # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
  system.stateVersion = "22.11"; # Did you read the comment?
}