diff --git a/node_external_ip_controller_async.py b/node_external_ip_controller_async.py
index 01dc675..06eb160 100644
--- a/node_external_ip_controller_async.py
+++ b/node_external_ip_controller_async.py
@@ -2,6 +2,7 @@ import asyncio
 from kubernetes_asyncio import client, config, watch
 import os
 import logging
+import ipaddress
 
 # Configuration
 ANNOTATION_KEY = os.getenv("ANNOTATION_KEY", "kube-vip.io/loadbalancerIPs")
@@ -17,6 +18,14 @@ logging.basicConfig(level=logging.DEBUG)
 logger = logging.getLogger(__name__)
 
 
+def is_valid_ip(ip):
+    try:
+        ipaddress.ip_address(ip)
+        return True
+    except ValueError:
+        return False
+
+
 async def update_service_annotation(v1, service, external_ips):
     try:
         service_name = service.metadata.name
@@ -27,7 +36,15 @@ async def update_service_annotation(v1, service, external_ips):
         current_annotation = service_obj.metadata.annotations.get(ANNOTATION_KEY)
         zlan_gateway_ip = service_obj.metadata.labels.get(SERVICE_LABEL_KEY)
         logger.debug(f"Zlan Gateway IP: {zlan_gateway_ip}")
-        target_annotation = ",".join(external_ips) + "," + zlan_gateway_ip
+
+        if is_valid_ip(zlan_gateway_ip):
+            target_annotation = ",".join(external_ips) + "," + zlan_gateway_ip
+        else:
+            target_annotation = ",".join(external_ips)
+            logger.debug(
+                f"Invalid Zlan Gateway IP: {zlan_gateway_ip}, excluding from target annotation"
+            )
+
         logger.debug(f"Current annotation: {current_annotation}")
         logger.debug(f"Target annotation: {target_annotation}")
         if current_annotation != target_annotation: