diff --git a/port.json b/port.json
new file mode 100644
index 0000000..17fdad0
--- /dev/null
+++ b/port.json
@@ -0,0 +1,11 @@
+{
+  "version": 3,
+  "rules": [
+    {
+      "port": [],
+      "port_range": [
+        "21000:21999"
+      ]
+    }
+  ]
+}