diff --git a/plugin/virtualRouterProvider/src/main/java/org/zstack/network/service/virtualrouter/portforwarding/PortForwardingConfigProxy.java b/plugin/virtualRouterProvider/src/main/java/org/zstack/network/service/virtualrouter/portforwarding/PortForwardingConfigProxy.java
index feff1ea1f01..2a1b8dd4920 100644
--- a/plugin/virtualRouterProvider/src/main/java/org/zstack/network/service/virtualrouter/portforwarding/PortForwardingConfigProxy.java
+++ b/plugin/virtualRouterProvider/src/main/java/org/zstack/network/service/virtualrouter/portforwarding/PortForwardingConfigProxy.java
@@ -35,6 +35,9 @@ protected void attachNetworkServiceToNoHaVirtualRouter(String vrUuid, String typ
 
     @Override
     protected void detachNetworkServiceFromNoHaVirtualRouter(String vrUuid, String type, List<String> serviceUuids) {
+        if (serviceUuids == null || serviceUuids.isEmpty()) {
+            return;
+        }
         SQL.New(VirtualRouterPortForwardingRuleRefVO.class).eq(VirtualRouterPortForwardingRuleRefVO_.virtualRouterVmUuid, vrUuid)
                 .in(VirtualRouterPortForwardingRuleRefVO_.uuid, serviceUuids).delete();
     }
diff --git a/testlib/src/main/java/org/zstack/testlib/VirtualRouterOfferingSpec.groovy b/testlib/src/main/java/org/zstack/testlib/VirtualRouterOfferingSpec.groovy
index 1279c3a47df..db49c2ab57c 100755
--- a/testlib/src/main/java/org/zstack/testlib/VirtualRouterOfferingSpec.groovy
+++ b/testlib/src/main/java/org/zstack/testlib/VirtualRouterOfferingSpec.groovy
@@ -141,6 +141,10 @@ class VirtualRouterOfferingSpec extends InstanceOfferingSpec {
                 return new VirtualRouterCommands.SetSNATRsp()
             }
 
+            simulator(VirtualRouterConstant.VR_REMOVE_SNAT_PATH) {
+                return new VirtualRouterCommands.RemoveSNATRsp()
+            }
+
             simulator(VirtualRouterCentralizedDnsBackend.SET_DNS_FORWARD_PATH) {
                 return new VirtualRouterCommands.SetForwardDnsRsp()
             }