diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.Host/OpcUa/OtOpcUaServerHostedService.cs b/src/Server/ZB.MOM.WW.OtOpcUa.Host/OpcUa/OtOpcUaServerHostedService.cs
index 2819657b..cddf546c 100644
--- a/src/Server/ZB.MOM.WW.OtOpcUa.Host/OpcUa/OtOpcUaServerHostedService.cs
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.Host/OpcUa/OtOpcUaServerHostedService.cs
@@ -139,6 +139,45 @@ public sealed class OtOpcUaServerHostedService : IHostedService, IAsyncDisposabl
             }
         });
 
+        // Wire the reverse-path native-alarm-ack router (H6e): a client Acknowledge of a NATIVE (driver-fed,
+        // e.g. Galaxy) Part 9 condition that passes the node manager's AlarmAck gate routes the acknowledge to
+        // the owning driver child. The node manager maps the inbound ack to an OpcUaServer-local NativeAlarmAck;
+        // HERE the host maps that to the Runtime DriverHostActor.RouteNativeAlarmAck (field-for-field) and Tells
+        // it into the local DriverHostActor, which Primary-gates + resolves the owning DriverInstanceActor. The
+        // mapping happens at this boundary so Runtime stays free of an OpcUaServer dependency. The Tell is
+        // fire-and-forget so the handler — which runs under the SDK's Lock — never blocks. The DriverHostActor
+        // ref is resolved LAZILY per ack (this StartAsync runs before the Akka DriverHostActor registers, so a
+        // one-shot resolve here would always miss); by ack time the registry has it, mirroring the node-write
+        // gateway below.
+        _server.SetNativeAlarmAckRouter(nativeAck =>
+        {
+            try
+            {
+                if (_actorRegistry.TryGet<DriverHostActorKey>(out var driverHost))
+                {
+                    driverHost.Tell(new DriverHostActor.RouteNativeAlarmAck(
+                        nativeAck.ConditionNodeId, nativeAck.Comment, nativeAck.OperatorUser));
+                }
+                else
+                {
+                    // No driver host registered yet (admin-only node, or pre-registration race). The Part 9 ack
+                    // already committed the local condition state; the missed routing surfaces as a non-applied
+                    // upstream acknowledge, not a client-visible error.
+                    _logger.LogWarning(
+                        "OtOpcUaServerHostedService: native alarm ack for {ConditionNodeId} dropped — no DriverHostActor registered",
+                        nativeAck.ConditionNodeId);
+                }
+            }
+            catch (Exception ex)
+            {
+                // The router runs under the SDK Lock on a server thread; a hiccup must not escape into the SDK's
+                // Call path. Log + drop — the client still gets Good for the condition-state change.
+                _logger.LogWarning(ex,
+                    "OtOpcUaServerHostedService: failed to route native alarm ack for {ConditionNodeId}",
+                    nativeAck.ConditionNodeId);
+            }
+        });
+
         // Wire the reverse-path inbound operator-write gateway: a client write to a writable equipment-tag
         // node that passes the node manager's WriteOperate gate routes the write to the owning driver child
         // (RouteNodeWrite → NodeWriteResult) via the local DriverHostActor. The node manager calls the
@@ -185,6 +224,8 @@ public sealed class OtOpcUaServerHostedService : IHostedService, IAsyncDisposabl
         _deferredServiceLevel.SetInner(null);
         // Restore the Null write gateway so a late client write doesn't Ask a stopping DriverHostActor.
         _server?.SetNodeWriteGateway(null);
+        // Clear the native-alarm-ack router so a late ack doesn't Tell a stopping DriverHostActor.
+        _server?.SetNativeAlarmAckRouter(null);
         // Restore the Null historian so a late HistoryRead doesn't hit a disposed read client.
         _server?.SetHistorianDataSource(null);
         return Task.CompletedTask;
diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaSdkServer.cs b/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaSdkServer.cs
index 48fbdc1d..fcc7a52d 100644
--- a/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaSdkServer.cs
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaSdkServer.cs
@@ -37,6 +37,27 @@ public sealed class OtOpcUaSdkServer : StandardServer
         return true;
     }
 
+    /// <summary>
+    ///     Wire the reverse-path router for inbound Part 9 Acknowledge of a NATIVE (driver-fed, e.g. Galaxy)
+    ///     condition onto the created <see cref="OtOpcUaNodeManager"/>. The host calls this after start with a
+    ///     non-blocking router that Tells a <c>DriverHostActor.RouteNativeAlarmAck</c> into the local
+    ///     <c>DriverHostActor</c>, which (Primary-gated) routes the acknowledge to the owning driver child.
+    ///     Native conditions are not owned by the scripted-alarm engine, so the node manager branches their
+    ///     inbound Acknowledge to this seam instead of the scripted <see cref="SetAlarmCommandRouter"/> path.
+    ///     Passing <c>null</c> clears it. No-op (returns <c>false</c>) when the node manager has not been
+    ///     created yet, so the caller can detect a too-early call (mirrors <see cref="SetAlarmCommandRouter"/>).
+    /// </summary>
+    /// <param name="router">The router invoked by the native condition's Acknowledge handler once the
+    /// <c>AlarmAck</c> gate passes; may be <c>null</c> to clear it.</param>
+    /// <returns><c>true</c> when the router was set on a live node manager; <c>false</c> when no node
+    /// manager exists yet.</returns>
+    public bool SetNativeAlarmAckRouter(Action<NativeAlarmAck>? router)
+    {
+        if (_otOpcUaNodeManager is null) return false;
+        _otOpcUaNodeManager.NativeAlarmAckRouter = router;
+        return true;
+    }
+
     /// <summary>
     ///     Wire the reverse-path gateway for inbound operator writes to writable equipment-tag nodes onto the
     ///     created <see cref="OtOpcUaNodeManager"/>. The host calls this after start with an