Alibaba Cloud CDN follows the protocol specified by the origin protocol policy to retrieve resources from an origin server. After you configure the origin protocol policy, Alibaba Cloud CDN redirects HTTP requests to port 80 or HTTPS requests to port 443. The protocol that Alibaba Cloud CDN uses is determined by the origin protocol policy.

Background information

The protocol policy supports only port 80 and port 443. Custom ports are not supported. If you want to use a custom port, to request Alibaba Cloud to configure relevant settings.

Procedure

  1. Log on to the Alibaba Cloud CDN console.
  2. In the left-side navigation pane, click Domain Names.
  3. On the Domain Names page, find the domain name that you want to manage and click Manage in the Actions column of the domain name.
  4. In the management pane of the domain name, click Back-to-origin.
  5. In the Origin Protocol Policy section, turn on Origin Protocol Policy.
  6. Click Modify.
  7. In the Static Origin Protocol Policy dialog box, set Redirect Type to Follow, HTTP, or HTTPS based on your business requirements.
    Parameter Description
    Follow Follow: When a client sends an HTTP or an HTTPS request, Alibaba Cloud CDN redirects the request to the origin server over the protocol used by the client.
    Note
    • Scenario: You can use the origin protocol policy to encrypt data transfer and protect data from unauthorized modifications or recording. However, HTTPS consumes additional computing resources on an origin server. In this case, you can choose to transmit only sensitive data such as user identity data over HTTPS, and transmit insensitive data such as images and video files over HTTP. Therefore, we recommend that you set the origin protocol policy to follow. Requests are transmitted between the origin server and clients over the protocol that is used by the clients.
    • Notes: To set the origin protocol policy to HTTPS or follow, the origin server must support HTTPS and has the TCP port open. HTTPS requests are typically redirected to port 443. If Alibaba Cloud CDN uses HTTPS, requests are redirected to port 443 by default. If you want to use a custom port, submit a ticket.
    • If you set the origin protocol policy to Follow, client requests are redirected to the origin server over HTTP or HTTPS. Make sure that both port 443 and port 80 are open on the origin server. Otherwise, Alibaba Cloud CDN fails to redirect client requests to the origin server.
    HTTP Alibaba Cloud CDN communicates with the origin server only over HTTP.
    HTTPS Alibaba Cloud CDN communicates with the origin server only over HTTPS.
    Origin protocol policy
  8. Click OK.