Connection Methods

You can access DDS over private or public networks.

**Table 1** Connection methods
Method	IP Address	Scenario	Description
Private network	Private IP address	DDS provides a private IP address by default. If your applications are running on an ECS that is in the same region, AZ, and VPC subnet as your DDS DB instance, you are advised to use a private IP address to connect the ECS to your DDS DB instances. By default, DDS is not accessible from ECSs that are not in the same security group. If the ECS is not in the same group, you need to add an inbound rule to enable access. The default DDS port is 8635, but this port can be modified if necessary.	Secure and excellent performance
Public network	EIP	If your applications are running on an ECS that is in a different region from the one where the DB instance is located, you are advised to use an EIP to connect the ECS to your DDS DB instances. If your applications are deployed on another cloud platform, EIP is recommended.	Low security For faster transmission and improved security, you are advised to migrate your applications to an ECS that is in the same subnet as your DDS instance and use a private IP address to access the instance.