nixos-config/modules/services/nas/nfs.nix

{config, pkgs, lib, ...}: {
  # enable nfs
  services.nfs.server = rec {
      enable = true;
      exports = ''
          /export         192.168.2.0/24(rw,fsid=0,no_subtree_check)
          /export/Pluto   192.168.2.0/24(rw,no_subtree_check)
          /export/Mars    192.168.2.0/24(rw,no_subtree_check)
      '';
      createMountPoints = true;
  };
  # open the firewall
  networking.firewall = {
    interfaces.enp6s18 = {
      allowedTCPPorts = [ 2049 ];
    };
  };
}