diff --git a/gio/gnetworkmonitorportal.c b/gio/gnetworkmonitorportal.c
index 77fd46654..3c4c2f696 100644
--- a/gio/gnetworkmonitorportal.c
+++ b/gio/gnetworkmonitorportal.c
@@ -92,6 +92,20 @@ g_network_monitor_portal_get_property (GObject    *object,
     }
 }
 
+static gboolean
+is_valid_connectivity (guint32 value)
+{
+  GEnumValue *enum_value;
+  GEnumClass *enum_klass;
+
+  enum_klass = g_type_class_ref (G_TYPE_NETWORK_CONNECTIVITY);
+  enum_value = g_enum_get_value (enum_klass, value);
+
+  g_type_class_unref (enum_klass);
+
+  return enum_value != NULL;
+}
+
 static void
 got_available (GObject *source,
                GAsyncResult *res,
@@ -228,7 +242,8 @@ got_connectivity (GObject *source,
       g_variant_unref (ret);
     }
 
-  if (nm->priv->connectivity != connectivity)
+  if (nm->priv->connectivity != connectivity &&
+      is_valid_connectivity (connectivity))
     {
       nm->priv->connectivity = connectivity;
       g_object_notify (G_OBJECT (nm), "connectivity");
@@ -292,7 +307,8 @@ got_status (GObject *source,
       should_emit_changed = TRUE;
     }
 
-  if (nm->priv->connectivity != connectivity)
+  if (nm->priv->connectivity != connectivity &&
+      is_valid_connectivity (connectivity))
     {
       nm->priv->connectivity = connectivity;
       g_object_notify (G_OBJECT (nm), "connectivity");
@@ -361,7 +377,8 @@ proxy_properties_changed (GDBusProxy            *proxy,
   if (ret)
     {
       GNetworkConnectivity connectivity = g_variant_get_uint32 (ret);
-      if (nm->priv->connectivity != connectivity)
+      if (nm->priv->connectivity != connectivity &&
+          is_valid_connectivity (connectivity))
         {
           nm->priv->connectivity = connectivity;
           g_object_notify (G_OBJECT (nm), "connectivity");