diff --git a/fast_trace/basic.go b/fast_trace/basic.go
index d51720cf..fd86a1ee 100644
--- a/fast_trace/basic.go
+++ b/fast_trace/basic.go
@@ -171,6 +171,7 @@ var Hangzhou = BackBoneCollection{
 	CU169: ISPCollection{
 		ISPName: CU169,
 		IP:      "ipv4.hgh-4837.endpoint.nxtrace.org.",
+		IPv6:    "ipv6.hgh-4837.endpoint.nxtrace.org.",
 	},
 	CM: ISPCollection{
 		ISPName: CM,
diff --git a/fast_trace/fast_trace ipv6.go b/fast_trace/fast_trace ipv6.go
index 68a0ad25..b3acebee 100644
--- a/fast_trace/fast_trace ipv6.go	
+++ b/fast_trace/fast_trace ipv6.go	
@@ -94,6 +94,7 @@ func (f *FastTracer) testCU_v6() {
 	f.tracert_v6(TestIPsCollection.Beijing.Location, TestIPsCollection.Beijing.CU169)
 	f.tracert_v6(TestIPsCollection.Shanghai.Location, TestIPsCollection.Shanghai.CU169)
 	f.tracert_v6(TestIPsCollection.Shanghai.Location, TestIPsCollection.Shanghai.CU9929)
+	f.tracert_v6(TestIPsCollection.Hangzhou.Location, TestIPsCollection.Hangzhou.CU169)
 	f.tracert_v6(TestIPsCollection.Guangzhou.Location, TestIPsCollection.Guangzhou.CU169)
 }