add disable public endpoint (#16147)

* add disable public endpoint

* restructure the doc

* fix

* fix

* Apply suggestions from code review

Co-authored-by: Ran <[email protected]>

* Apply suggestions from code review

* Apply suggestions from code review

Co-authored-by: Grace Cai <[email protected]>

---------

Co-authored-by: Ran <[email protected]>
Co-authored-by: Grace Cai <[email protected]>

tidb-cloud/connect-via-standard-connection-serverless.md

@@ -5,7 +5,9 @@ summary: Learn how to connect to your TiDB Serverless cluster via public endpoin
 
 # Connect to TiDB Serverless via Public Endpoint
 
-This document describes how to connect to your TiDB Serverless cluster via a public endpoint, using a SQL client from your computer.
+This document describes how to connect to your TiDB Serverless cluster via a public endpoint, using a SQL client from your computer, as well as how to disable a public endpoint.
+
+## Connect via a public endpoint
 
 > **Tip:**
 >
@@ -34,6 +36,28 @@ To connect to a TiDB Serverless cluster via public endpoint, take the following
     >
     > When you connect to a TiDB Serverless cluster, you must include the prefix for your cluster in the user name and wrap the name with quotation marks. For more information, see [User name prefix](/tidb-cloud/select-cluster-tier.md#user-name-prefix).
 
+## Disable a public endpoint
+
+If you do not need to use a public endpoint of a TiDB Serverless cluster, you can disable it to prevent connections from the internet:
+
+1. Navigate to the [**Clusters**](https://tidbcloud.com/console/clusters) page, and then click the name of your target cluster to go to its overview page.
+
+2. Click **Networking** in the left navigation pane and click **Disable** in the right pane. A confirmation dialog is displayed.
+
+3. Click **Disable** in the confirmation dialog.
+
+After disabling the public endpoint, the `Public` entry in the **Endpoint Type** drop-down list of the connect dialog is disabled. If users are still trying to access the cluster from the public endpoint, they will get an error.
+
+> **Note:**
+>
+> Disabling the public endpoint does not affect existing connections. It only prevents new connections from the internet.
+
+You can re-enable the public endpoint after disabling it:
+
+1. Navigate to the [**Clusters**](https://tidbcloud.com/console/clusters) page, and then click the name of your target cluster to go to its overview page.
+
+2. Click **Networking** in the left navigation pane and click **Enable** in the right pane.
+
 ## What's next
 
 After you have successfully connected to your TiDB cluster, you can [explore SQL statements with TiDB](/basic-sql-operations.md).