(Optional) Configuring SSL Connection

GaussDB(DWS) supports connections in SSL authentication mode so that data transmitted between the GaussDB(DWS) client and the database can be encrypted. The SSL mode delivers higher security than the common mode. By default, the SSL function is enabled in a cluster to allow SSL or non-SSL connections from the client. For security purposes, you are advised to enable SSL connection. If you want to use SSL connection, enable Require SSL Connection for the cluster.

On the Security Settings page of the cluster, you can enable or disable Require SSL Connection.

After you have changed the security setting parameters and the settings take effect, the cluster may be restarted, which makes the cluster unavailable temporarily.
To modify the cluster's security configuration, ensure that the following conditions are met:
- The cluster status is Available or Unbalanced.
- The value of Task Information cannot be Creating snapshot, Scaling out, Configuring, or Restarting.

The following parts are included in this section:

Configuring SSL Connection
Combinations of SSL Connection Parameters on the Client and Server

Configuring SSL Connection

Log in to the GaussDB(DWS) management console.
In the navigation pane on the left, click Clusters.
In the cluster list, click the name of a cluster. On the page that is displayed, click Security Settings.
By default, Configuration Status is set to Synchronized, which indicates that the latest database result is displayed.
In the SSL Connection area, enable Require SSL Connection (recommended).
indicates that the server requires SSL connection.

indicates that no SSL connection is required (default).
- If the gsql client or ODBC driver provided by GaussDB(DWS) is used, GaussDB(DWS) supports the TLSv1.2 SSL protocol.
- If the JDBC driver provided by GaussDB(DWS) is used, GaussDB(DWS) supports SSL protocols, such as SSLv3, TLSv1, TLSv1.1, and TLSv1.2. The SSL protocol used between the client and the database depends on the Java Development Kit (JDK) version used by the client. Generally, JDK supports multiple SSL protocols.
Click Apply.
The system automatically saves the SSL connection settings. On the Security Settings page, Configuration Status is Applying. After Configuration Status changes to Synchronized, the settings have been saved and taken effect.

Combinations of SSL Connection Parameters on the Client and Server

Whether the client uses the SSL encryption connection mode and whether to verify the server certificate depend on client parameter sslmode and server (cluster) parameters ssl and require_ssl. The parameters are described as follows:

ssl (Server)
The ssl parameter indicates whether to enable the SSL function. on indicates that the function is enabled, and off indicates that the function is disabled.
- The default value is on for clusters whose version is 1.3.1 or later, and you cannot set this parameter on the GaussDB(DWS) management console.
- For clusters whose version is earlier than 1.3.1, the default value is on. You can set this parameter in the SSL Connection area on the cluster's Security Settings page of the GaussDB(DWS) management console.
require_ssl (Server)
The require_ssl parameter specifies whether the server forcibly requires SSL connection. This parameter is valid only when ssl is set to on. on indicates that the server forcibly requires SSL connection. off indicates that the server does not require SSL connection.
- The default value is off for clusters whose version is 1.3.1 or later. You can set the require_ssl parameter in the Require SSL Connection area of the cluster's Security Settings page on the GaussDB(DWS) management console.
- For clusters whose version is earlier than 1.3.1, the default value is off, and you cannot set this parameter on the GaussDB(DWS) management console.
sslmode (Client)
You can set this parameter in the SQL client tool.
- In the gsql command line client, this parameter is the PGSSLMODE parameter.
- On the Data Studio client, this parameter is the SSL Mode parameter.

The combinations of client parameter sslmode and server parameters ssl and require_ssl are as follows.

**Table 1** Combinations of SSL connection parameters on the client and server
ssl (Server)	sslmode (Client)	require_ssl (Server)	Result
on	disable	on	The server requires SSL, but the client disables SSL for the connection. As a result, the connection cannot be set up.
	disable	off	The connection is not encrypted.
	allow	on	The connection is encrypted.
	allow	off	The connection is not encrypted.
	prefer	on	The connection is encrypted.
	prefer	off	The connection is encrypted.
	require	on	The connection is encrypted.
	require	off	The connection is encrypted.
	verify-ca	on	The connection is encrypted and the server certificate is verified.
	verify-ca	off	The connection is encrypted and the server certificate is verified.
off	disable	on	The connection is not encrypted.
	disable	off	The connection is not encrypted.
	allow	on	The connection is not encrypted.
	allow	off	The connection is not encrypted.
	prefer	on	The connection is not encrypted.
	prefer	off	The connection is not encrypted.
	require	on	The client requires SSL, but SSL is disabled on the server. Therefore, the connection cannot be set up.
	require	off	The client requires SSL, but SSL is disabled on the server. Therefore, the connection cannot be set up.
	verify-ca	on	The client requires SSL, but SSL is disabled on the server. Therefore, the connection cannot be set up.
	verify-ca	off	The client requires SSL, but SSL is disabled on the server. Therefore, the connection cannot be set up.