Connecting a Database

The following table lists the common methods for connecting to a DDS instance.

**Table 1** Connection methods
Method	IP Address	Scenario	Description
Private network connection (recommended)	Private IP address	DDS provides a private IP address by default. If your applications are deployed on ECS and located in the same region, AZ, and VPC subnet as the DB instance, you are advised to use a private IP address to connect to the DB instance. By default, a DDS instance is not accessible from an ECS in a different security group. Add an inbound rule to the DDS security group to allow access of the ECS. The default DDS port is 8635. You can change it if you want to access DDS through another port.	Secure and excellent performance
Public network connection	EIP	If your applications are running on an ECS that is in a different region from the one where the DDS instance is located, use an EIP to connect the ECS to your DDS instances. If your applications are deployed on other cloud platforms, EIP is recommended.	Low security
Application connection	Private IP address	Connect to the database using different applications.	Connecting to the Database Using Java Connecting to the Database Using Python