If the IP address of your origin server is associated with multiple domain names, and requests are redirected to the origin server over HTTPS, you must configure the origin Server Name Indication (SNI) feature for the origin server. Origin SNI specifies the domain name to which requests are destined, and allows the server to return the correct certificate.

Background information

SNI is an extension of Transport Layer Security (TLS) and Secure Sockets Layer (SSL) by which a client determines which hostname it is attempting to connect to at the beginning of the handshake process. SNI allows a server to present multiple SSL certificates on the same IP address. After origin SNI is enabled, when a Dynamic Route for CDN (DCDN) node sends a TLS handshake request to the origin server, the origin server determines the requested domain name based on the SNI information provided by the TLS handshake request. Then, the origin server returns the correct SSL certificate.

Notice
  • The origin server must be able to parse SNI information provided by the TLS handshake request from DCDN nodes.
  • If multiple origin servers are configured for an accelerated domain name, you can configure the origin SNI feature in the DCDN console. In this case, all back-to-origin requests point to the domain name that corresponds to the SNI value. If you want to set different SNI values for different origin servers, submit ticket.
The following figure shows how origin SNI works. How origin SNI works
Origin SNI works based on the following process:
  1. A DCDN node redirects a request to the origin server over HTTPS. The domain name for which the request is destined is specified by SNI.
  2. After the origin server receives the request, it responds with the certificate of the requested domain name based on SNI.
  3. After the DCDN node receives the certificate, it establishes a secure connection with the origin server.

Procedure

  1. Log on to the DCDN 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 Configure in the Actions column.
  4. In the left-side navigation pane on the details page of the specified domain name, click Origin Fetch.
  5. On the Origin Fetch tab, find Origin SNI.
  6. Turn on Origin SNI and enter the domain name from which clients can retrieve resources, for example, dcdn.console.aliyun.com.
    Note SNI supports only specific domain names. Wildcard domain names are not supported.
    Origin SNI
  7. Click OK.