anchor.diff:          preStart =
             ''
               set +e # continue in case of errors
  +
  +            # Create virtual network interfaces
  +            ${flip concatMapStrings cfg.interfaces (i:
  +              optionalString i.virtual
  +                ''
  +                  echo "Creating virtual network interface ${i.name}..."
  +                  ${pkgs.tunctl}/bin/tunctl -t "${i.name}" -u "${i.virtualOwner}"
  +                '')
  +            }
   
               # Set MAC addresses of interfaces, if desired.
               ${flip concatMapStrings cfg.interfaces (i:
  
positive.code:           '';
          };
  
        };
  
      };
  
negative.code:         pkgs.openresolv
        ]
        ++ optional (cfg.bridges != {}) pkgs.bridge_utils
        ++ optional hasVirtuals pkgs.tunctl
        ++ optional cfg.enableIPv6 pkgs.ndisc6;
  
      security.setuidPrograms = [ "ping" "ping6" ];
  