Update: tips about warnning log
@@ -61,7 +61,10 @@ server {
```
## istio/envoy
-If you using [Istio](https://istio.io/) ingressgateway or [Envoy](https://www.envoyproxy.io/) as reverse proxy, there are some tips for you.
+If you using [Istio](https://istio.io/) ingressgateway or [Envoy](https://www.envoyproxy.io/) as reverse proxy, there are some tips for you. If not set, you may see some debug log in proxy as below:
+```log
+Sending local reply with details upgrade_failed
+```
### Envoy
You need add a new upgrade_type named `tailscale-control-protocol`. [see detail](https://www.envoyproxy.io/docs/envoy/latest/api-v3/extensions/filters/network/http_connection_manager/v3/http_connection_manager.proto#extensions-filters-network-http-connection-manager-v3-httpconnectionmanager-upgradeconfig)
