diff --git a/client/lib/state/nodes_provider.dart b/client/lib/state/nodes_provider.dart
index 9120d48..305a8ec 100644
--- a/client/lib/state/nodes_provider.dart
+++ b/client/lib/state/nodes_provider.dart
@@ -56,13 +56,18 @@ class NodesNotifier extends AsyncNotifier<List<Node>> {
   }
 
   /// 后台实测各节点延迟,完成后回填(notifier 未销毁才更新)。
+  /// 探测失败(返回 0,如连接态全局 TUN 把到节点的 TCP 握手接住)时**保留旧 ping**,
+  /// 不把已知延迟覆盖成空——否则连上后节点列表延迟会整列消失。
   Future<void> _measure(List<Node> list) async {
     if (list.isEmpty) return;
     final pings = await probeAll(
       [for (final n in list) (uuid: n.uuid, host: n.host, port: n.port)],
     );
     if (_disposed) return;
-    final updated = [for (final n in list) n.copyWith(ping: pings[n.uuid] ?? n.ping)];
+    final updated = [
+      for (final n in list)
+        n.copyWith(ping: (pings[n.uuid] ?? 0) > 0 ? pings[n.uuid]! : n.ping)
+    ];
     state = AsyncData(updated);
   }