Alibaba Cloud CDN supports TLS version control. You can enable TLS versions for your domain names as needed. Early versions of TLS will soon support outdated browsers but provide relatively low security. The latest versions of TLS provide enhanced security but may not be compatible with outdated browsers. This topic describes the concepts, use scenarios, and configuration method of TLS version control.

Background information

TLS is designed to ensure the security and integrity of data transmitted between two applications. A typical use case of TLS is HTTPS (HTTP over TLS). HTTPS, also known as HTTP over TLS, is a secure version of HTTP. HTTPS runs below the top application layer (HTTP) and above the transport layer (TCP), and provides data encryption and decryption services.
Protocol Description Supported browser
TLSv1.0 TLS 1.0 was defined in RFC 2246 in 1999 as an update to SSL 3.0. TLS 1.0 is vulnerable to various attacks, such as BEAST and POODLE attacks. TLS 1.0 is no longer recommended for network protection due to the weak encryption performance. TLS 1.0 is not compliant with Payment Card Industry Data Security Standard (PCI DSS).
  • Internet Explorer 6 and later
  • Google Chrome 1 and later
  • Firefox 2 and later
TLSv1.1 TLS 1.1 was defined in RFC 4346 in 2006 as an update to TLS 1.0. TLS 1.1 fixed some vulnerabilities in TLS 1.0.
  • Internet Explorer 11 and later
  • Google Chrome 22 and later
  • Firefox 24 and later
  • Safari 7 and later
TLSv1.2 TLS 1.2 was defined in RFC 5246 in 2008 and is a widely used TLS version.
  • Internet Explorer 11 and later
  • Google Chrome 30 and later
  • Firefox 27 and later
  • Safari 7 and later
TLSv1.3 TLS 1.3 was defined in RFC 8446 in 2018 as the latest TLS version. TLS 1.3 supports the zero round trip time resumption (0-RTT) mode and allows you to establish faster connections. TLS 1.3 supports only key exchange algorithms of perfect forward secrecy to enhance security.
  • Google Chrome 70 and later
  • Firefox 63 and later


An SSL certificate is configured for the domain name. For more information, see Configure an SSL certificate.

Note TLS 1.0, TLS 1.1, and TLS 1.2 are enabled by default.
  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 HTTPS.
  5. In the TLS Version Control section, you can enable or disable specific TLS versions based on your business requirements.
    For more information about TLS versions. TLS version control

Recommended versions

Scenario Recommended version
Require compatibility with browsers and security is not a priority TLSv1.0, TLSv1.1, and TLSv1.2
Security is a priority and incompatibility with some browsers is acceptable TLSv1.2
Early Adopters TLSv1.0, TLSv1.1, TLSv1.2, and TLSv1.3