Configuring CDN Settings
Introduction
CDN settings allow you to adjust basic parameters of the CDN resource.
This Help Center article assumes you have an active CDN resource
Browser Cache TTL
The browser cache TTL (Time-To-Live) determines how long CDN responses should be stored in the browser cache. Modern browsers also check whether the server-side response has changed and, if necessary, synchronize it with the local cache.
Tip: To achieve the best possible score in Google PageSpeed Insights, you should set the value as high as possible. Google recommends a TTL of at least one year (365 days).
You can also find more information on the optimal cache time in the Google PageSpeed documentation.
Note: Changes to the TTL always apply to static resources with a caching type of MISS or STALE. Existing resources that are already being served by the CDN (HIT) are not affected by the change.
CDN Cache TTL
The CDN cache TTL controls how often a static file should be synchronized with the origin server. If you frequently replace content at the same URL, you should select a short TTL here.
Caution: Selecting a very short TTL can result in a very high number of HTTP requests to your destination server. Only select a short TTL if you frequently update content at the same URL.
HTTPS Redirection
When this setting is enabled, all HTTP requests are redirected to HTTPS using a 301 code.
AVIF Support
When this setting is enabled, all JPG and JPEG files are additionally converted to AVIF. If the requesting browser supports the AVIF format, the newly generated AVIF file is served instead of the original image file.
Support for the AVIF format is determined via the HTTP-Accept header.
WebP Support
When this setting is enabled, all JPG, JPEG, and PNG files are additionally converted to WebP. If the requesting browser supports the WebP format, the newly generated WebP file is served instead of the original image file.
The check to determine whether the browser supports the WebP format is controlled via the HTTP-Accept header.
Ignore Query Strings
When this setting is enabled, all HTTP parameters following the "?" are ignored. This setting is particularly useful for tracking URLs.
CORS Origin Header
Once this setting is enabled, all HTTP responses are extended with an "Access-Control-Allow-Origin:" header. The header is automatically set to the target server. For example: "Access-Control-Allow-Origin: https://deineseite.de". Static files that are already in the cache are not affected by this.
For more information on Cross-Origin Resource Sharing (CORS), see the official Mozilla documentation.
Canonical Header
Enabling the Canonical Header setting adds a "Link" header to all HTTP responses. The header is automatically directed to the target server to prevent duplicate content.
Root Document Behavior
The Root Document Behavior setting controls how the system handles requests to the root directory of the CDN domain. Here, you can choose between the settings Allow Access and Deny Access.
When set to Allow Access, the incoming request is transparently forwarded to the defined target server. To prevent duplicate content, the CDN HTTP response includes a Canonical header with the target server definition.
When set to Deny Access, incoming HTTP requests are immediately responded to with a 403 error.
HTTP Authentication
If the target server is protected by HTTP Basic Authentication, the login credentials for the target server can be entered here. The HTTP Authorization header is then included in every request sent to the target server.