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ENS:Configure an HTTP listener

Last Updated:Aug 26, 2026

Add an HTTP listener to an ELB instance to forward HTTP requests to backend servers. An HTTP listener is suitable for applications that do not require encrypted communication, such as internal network communication, test and development environments, and transmission of non-sensitive information.

Prerequisites

You have created an ELB instance. For instructions, see Create an ELB instance.

Procedure

  1. Log on to theENS console

  2. On the ELB Instance management page, find the instance that you want to configure, and then click Listener Configuration in the Actions column.

  3. On the Listener tab, click Add Listener.

  4. Configure the basic information. The following table describes the parameters.

    Parameter

    Description

    Listener Name

    A custom name for the listener.

    Load balancing protocol

    Select HTTP.

    Listening Port

    The listener port that receives requests and forwards them to backend servers. Valid values: 1 to 65535.

    Note

    Port 80 is recommended for HTTP.

    Advanced Settings

    Click Modify to expand the advanced settings.

    Scheduling Algorithm

    • Weighted Round-Robin (WRR): A backend server with a higher weight has a higher probability of receiving requests.

    • Weighted Least Connections (WLC): Requests are distributed based on the weight that is configured for each backend server and the actual load of the server, which is the number of connections. If backend servers have the same weight, the server with fewer connections has a higher probability of receiving requests.

    • Round-Robin (RR): External requests are distributed to backend servers in sequence based on the order in which the requests arrive.

    Redirection

    Specify whether to forward the traffic of the HTTP listener to an HTTPS listener.

    Note

    Before you enable this feature, make sure that you have created an HTTPS listener. For instructions, see Configure an HTTPS listener.

    Idle timeout

    If no request is received within the specified timeout period, the load balancer closes the current connection and establishes a new connection when the next request arrives. Valid values: 1 to 60. Unit: seconds.

    Request timeout

    If the backend server does not respond to a request within the request timeout period, the load balancer stops waiting and returns an HTTP 504 error code to the client.

    • Valid values: 1 to 180.

    • Unit: seconds.

    Get client IP address

    Backend servers can retrieve the real IP address of the client. This feature is enabled by default.

  5. Click Next and configure the health check. For more information about the parameters, see Health check.

  6. After you configure the health check, click Next. Verify that the settings are correct, and then click Create.

  7. After the configuration is complete, manually start the load balancing listener. On the Listener tab, click Start in the Actions column of the listener.