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?

No, UDP listeners do not support client affinity and 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?

10.

You can increase the quota on the Quota Center or Quota Management page. For more information, see Adjust quotas.

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
    • For each HTTP or HTTPS listener: 1
  • Custom routing listeners: 65499

    The following system reserved ports do not take effect: 25, 250, 4789, and 4790.

You can specify more than 300 consecutive ports for a TCP or UDP listener in specific regions. 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 your application 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 your application 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 the Proxy Protocol to preserve client IP addresses after you enable client IP address preservation. Therefore, you must make sure that the backend servers support the Proxy Protocol. Otherwise, the backend servers cannot parse the Proxy Protocol header.

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 listeners, you can disable client IP address preservation in the GA console. Perform the following steps:
  1. Log on to the GA console.
  2. On the Instances page, find the GA instance that you want to manage and click Configure Listeners in the Actions column.
  3. On the Listeners tab, find the listener that you want to manage and click Modify in the Actions column.
  4. On the Configure Listener & Protocol wizard page, click Next.
  5. On the Configure Endpoint Group wizard page, turn off Preserve Client IP and click Next.
  6. On the Confirm wizard page, confirm the information and click Submit.

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

GA supports Automatically Retrieve Client IP and Proxy Protocol to obtain client IP addresses.
Note If you use Proxy Protocol to obtain client IP addresses, make sure that the backend servers support Proxy Protocol. Otherwise, you cannot access backend servers. For more information about how to obtain client IP addresses, see Preserve client IP addresses.
The method that is used to obtain client IP addresses varies based on the listener protocol and where the backend service is deployed:
  • If the backend service is deployed on Alibaba Cloud:
    • TCP listener: You can use Automatically Retrieve Client IP and Proxy Protocol to obtain client IP addresses. To obtain the IP addresses of IPv6 clients, you must use Proxy Protocol.
    • HTTP or HTTPS listener: You can obtain client IP addresses only by using the X-Forwarded-For HTTP request header.
  • If the backend service is deployed Off Alibaba Cloud:
    • TCP listener: Proxy Protocol is used by default. To obtain the IP addresses of IPv6 clients, you must use Proxy Protocol.
    • HTTP or HTTPS listener: You can obtain client IP addresses only by using the X-Forwarded-For HTTP request header.