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    Global Accelerator:Listener FAQ

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    Global Accelerator:Listener FAQ

    Last Updated:Jun 24, 2025

    This topic provides answers to some frequently asked questions about listeners of Global Accelerator (GA).

    Does GA support client IP address preservation?

    Yes, GA supports client IP address preservation.

    Whether a GA instance supports client IP address preservation depends on the protocol that is used by the listener of the GA instance. For more information, see Preserve client IP addresses.

    Do UDP listeners support client affinity and client IP address preservation?

    UDP listeners do not support client affinity, but support client IP address preservation.

    Can different listeners of a GA instance use the same port?

    UDP listeners can use the same port as TCP, HTTP, or HTTPS listeners. However, TCP, HTTP, and HTTPS listeners cannot use the same port.

    What is the maximum number of listeners that I can add to a GA instance?

    50.

    You can increase quotas for a GA instance in the Quota Center or on the Quota Management page. For more information, see the "Adjust quotas" section of the Manage GA quotas topic.

    For more information about the limits of GA, see Limits.

    What is the maximum number of ports that I can configure for a listener?

    The number of ports supported by a listener by default varies based on the routing type of the listener and the protocol used for the routing type.

    • Intelligent routing listeners:

      • For each TCP or UDP listener: 30

        Note

        For more information about how to calculate the number of ports, see Intelligent routing listener ports.

      • For each HTTP or HTTPS listener: 1

    • Custom routing listeners: 65,499

    Depending on the billing method for GA instances, the maximum number of ports that can be configured for a single listener varies between TCP and UDP intelligent routing listeners. For more information, see Listener ports.

    You can specify a port range that contains more than 300 consecutive ports for a TCP or UDP listener. For more information, see Listener ports.

    What is the range of ports that I can configure for a listener?

    1 to 65499.

    Why do the backend servers fail to retrieve client IP addresses after I enable client IP address preservation?

    • If you use an HTTP or HTTPS listener and the backend server cannot record or process the X-Forwarded-For header, client IP address preservation does not take effect.

    • If you use a TCP listener:

      • If the backend service is deployed on Alibaba Cloud but the backend servers are not deployed in a virtual private cloud (VPC) or the elastic IP address (EIP) is not associated with an instance of the VPC type, the backend servers cannot preserve client IP addresses.

      • If the backend service is deployed outside Alibaba Cloud, the backend servers must support the Proxy Protocol so that they can preserve client IP addresses.

        This is because GA uses Proxy Protocol to preserve client IP addresses after you enable client IP address preservation. Therefore, you must make sure that the backend servers support Proxy Protocol. Otherwise, the backend servers cannot parse the Proxy Protocol header.

      • If the client uses an IPv6 address to access an IPv4 backend service, the backend servers must support Proxy Protocol. Otherwise, the backend servers cannot preserve client IP addresses.

    • If you use a UDP listener and the client uses an IPv6 address to access an IPv4 backend service, client IP address preservation does not take effect.

    For more information about the client IP address preservation feature of different types of listeners, see Preserve client IP addresses.

    How do I disable client IP address preservation?

    For HTTP listeners and HTTPS listeners, client IP address preservation is automatically enabled and cannot be disabled.

    For TCP and UDP listeners, you can disable client IP address preservation in the GA console. Perform the following steps:

    1. On the Instances page, find the GA instance that you want to manage and click Configure Listeners in the Actions column.

    2. On the Listeners tab, find the listener that you want to manage and click Mod Lsnr in the Actions column.

    3. In the Configure Listener & Protocol step, click Next.

    4. In the Configure Endpoint Group step, set Preserve Client IP to Do Not Preserve and click Next.

    5. In the Configuration Review step, confirm the information and click Submit.

    How do I obtain client IP addresses when IPv6 clients access IPv4 services of GA?

    • HTTP and HTTPS listeners obtain the client IP addresses of IPv6 and IPv4 clients by using the X-Forwarded-For HTTP header.

    • TCP listeners obtain the client IP addresses of IPv6 clients by using Proxy Protocol. This method requires that the backend servers support Proxy Protocol. Otherwise, access may fail.

    • UDP listeners cannot obtain the client IP addresses of IPv6 clients.

    For more information, see Preserve client IP addresses.