This topic describes how to fix the issue that an error is reported when you connect a source or destination database instance to Data Transmission Service (DTS) over Cloud Enterprise Network (CEN).

Usage notes

If you have questions about or requirements for CEN when you troubleshoot the issue, contact the technical support of CEN. For more information about CEN, see What is CEN?

Procedure

  1. Collect information about the source or destination database instance in which the error is reported.

    The following table describes the information to be collected about the database instance.

    Parameter Description
    Instance Region The region in which the self-managed database instance resides.
    CEN Instance ID The ID of the CEN instance that is connected to the self-managed database instance.
    Connected VPC The ID of the virtual private cloud (VPC) that is connected to the self-managed database instance.
    IP Address The private IP address of the self-managed database instance.
    Port Number The service port number of the self-managed database instance.
  2. Obtain the CIDR blocks of DTS servers in the region in which the database instance resides.
    In the CIDR blocks to add when an on-premises database is connected to Alibaba Cloud over CEN, Express Connect, VPN Gateway, Smart Access Gateway, or Database Gateway column of the table in the Whitelist DTS IP ranges for your user-created database topic, you can obtain the CIDR blocks of DTS servers based on the region in which the database instance resides.
  3. Check the security settings of the self-managed database instance.
    Make sure that all CIDR blocks of DTS servers are added to the security settings of the self-managed database instance. This way, accesses from DTS servers are allowed. The security settings include but are not limited to the following items:
    • Security groups of self-managed database instances
    • Firewalls of self-managed database instances
    • Whitelists of self-managed database instances
  4. Check the routing of the VPC that is connected to the self-managed database instance.

    Make sure that your database instance can be accessed from the VPC that you specified for the Connected VPC parameter. Then, provide the collected information for the technical support of CEN for troubleshooting.

  5. Check the routing of the data center in which the self-managed database instance is deployed.

    Check your data center and check whether packets that are sent to the CIDR blocks of DTS servers are sent back to CEN. If the packets that are sent to the CIDR blocks of DTS servers are sent back to CEN, provide the collected information for the technical support of CEN for troubleshooting.