diff --git a/TsinghuaNet/MainViewModel.vb b/TsinghuaNet/MainViewModel.vb
index 3177252..0584b06 100644
--- a/TsinghuaNet/MainViewModel.vb
+++ b/TsinghuaNet/MainViewModel.vb
@@ -76,7 +76,7 @@ Class MainViewModel
     End Property
 
     Public Event StateChanged As EventHandler(Of NetState)
-    Public Shared ReadOnly StateProperty As DependencyProperty = DependencyProperty.Register(NameOf(State), GetType(NetState), GetType(MainViewModel), New PropertyMetadata(NetState.Net, AddressOf StatePropertyChangedCallback))
+    Public Shared ReadOnly StateProperty As DependencyProperty = DependencyProperty.Register(NameOf(State), GetType(NetState), GetType(MainViewModel), New PropertyMetadata(NetState.Unknown, AddressOf StatePropertyChangedCallback))
     Public Property State As NetState
         Get
             Return GetValue(StateProperty)
@@ -156,6 +156,7 @@ Class MainViewModel
 End Class
 
 Enum NetState
+    Unknown
     Auth4
     Auth6
     Net
diff --git a/TsinghuaNet/MainWindow.xaml.vb b/TsinghuaNet/MainWindow.xaml.vb
index 802fe39..bdd19f4 100644
--- a/TsinghuaNet/MainWindow.xaml.vb
+++ b/TsinghuaNet/MainWindow.xaml.vb
@@ -116,6 +116,8 @@ Class MainWindow
         Select Case e
             Case NetState.Auth4
                 Auth4.IsChecked = True
+            Case NetState.Auth6
+                Auth6.IsChecked = True
             Case NetState.Net
                 Net.IsChecked = True
         End Select