diff --git a/plugins/modbus/modbus-tcp.json b/plugins/modbus/modbus-tcp.json
index 217dd830..348afc77 100644
--- a/plugins/modbus/modbus-tcp.json
+++ b/plugins/modbus/modbus-tcp.json
@@ -13,6 +13,7 @@
 		"attribute": "required",
 		"type": "string",
 		"valid": {
+			"regex": "/^((2[0-4]\\d|25[0-5]|[01]?\\d\\d?)\\.){3}(2[0-4]\\d|25[0-5]|[01]?\\d\\d?)$/",
 			"length": 30
 		}
 	},