In this article, you will learn:
- How the WEDOS Protection CDN cache works
- How to set up CDN cache
- Troubleshooting common issues
- Frequently asked questions
WEDOS Protection CDN Cache
WEDOS Protection caches content within its global network of proxy servers, which the web server returns with certain HTTP return codes, such as 200 (OK), 302 (Found), 304 (Not Modified), 307 (Temporary Redirect), and 404 (Not Found). It offers two configuration options:
- CDN static content caching doesn’t distinguish between cached file extensions and may cache dynamically generated pages (e.g. .php) if the server returns them with one of the listed codes and they are not specifically excluded from caching. This is the default setting for caching servers.
- CDN file caching focuses on caching specific file types based on their extensions. This mode is available in the Advanced plan and above, and allows you to customize the list of cached extensions.
The default CDN static content caching mode is more comprehensive and caches all content with the appropriate return codes. It is suitable for websites with a high volume of static content that want to maximize their performance. Website administrators who require precise control over the cached files, for example due to frequent content updates or specific performance requirements, will prefer to use CDN file caching.
The caching server keeps files in memory for 3 to 60 seconds, depending on the chosen plan. After this time, it asks the source server whether the content is still up-to-date. This short cache retention period is sufficient even for websites where the content is important, such as discussion forums.
The WEDOS Protection WordPress plugin offers both local and CDN caching.
CDN Cache Setup
To set up CDN cache, follow these steps:
- Log into the WEDOS Global admin panel ⧉.
- Select a domain (or template) to set up.
- In the left menu, click CDN Cache.
The available settings depend on the plan used:
- Start and above: Enable/disable, purge cache
- Advanced and above: Mode, Return Codes
- Expert and above: Exemptions, Hold Time, Threshold
Enable, Disable and Purge Cache
If content caching is causing problems that cannot be fixed in the code, you can turn it off at any time and turn it back on later.
If only the current cache status is problematic (for example, content that is not updated for some reason), simply purge it using the corresponding button.
Cache mode
If you are using the Advanced plan and higher, you can choose a caching mode. For a detailed description of the features of the available modes, see the WEDOS Protection CDN Cache chapter.
You can find the Behavior selector in the CDN Cache Mode section. There are no additional settings available for the CDN Static Content Caching mode, selecting the CDN File Caching mode will open an interface for managing cached file extensions. This will allow you to:
- Add/delete a file extension or group.
- Enable/disable caching of the selected extension or group.
The default list of cached extensions is: .png, .css, .jpg, .jpeg, .ico, .js, .webp, .gif, .svg, .woff2.
Return codes
If you are using the Advanced plan and higher, you can manage caching for return codes.
When CDN Cache for Return Codes is enabled you can:
- Add/delete a return code or group.
- Set hold time for each return code or group.
- Enable/disable caching of the selected extension or group.
Exemptions by URL
If you are using the Expert plan and higher, you can manage cache exemptions by URL.
When CDN Cache Exemptions by URL is enabled you can add/delete a URL path to be exempted from CDN Cache.
Hold time
If you are using the Expert plan and higher, you can manage cache hold time.
When CDN Cache Hold Time is enabled you can adjust the length of time that WGP keeps the CDN cache stored. The minimum is 60, the maximum/default is 86400.
Threshold
If you are using the Expert plan and higher, you can manage cache threshold.
When CDN Cache After a Certain Number of Uses is enabled you can adjust the threshold for when the page will start caching for a specific visitor. The default is 1 visit.
Troubleshooting Common Issues
Common issues with WEDOS Protection CDN cache include:
Outdated Cache Contents
Issue: Out-of-date content (such as an error message) remains in the cache.
Solution: Purge the cache using the corresponding button in the administration panel.
Disabling Cache Doesn’t Work
Issue: The cache is disabled, but the problem on the website persists.
Cause: The content may be cached elsewhere.
Solution: Make sure to clear all cached content. In the case of a browser, the keyboard shortcut Ctrl+Shift+R usually helps, and also check the cache settings in your content management system.
FAQ
If my content is already cached using on my web server, should I still use WEDOS Protection CDN?
Usually, a web server caches content itself. WEDOS Protection caches content on special servers located around the world, ensuring faster response – the content is physically closer and does not use up the web server’s resources, which reduces load and enables it to serve more users at less expense.
Is it possible to bypass the cache using query parameters?
Yes, if you submit a yet uncached query parameter (such as ?q=something) in the URL, you will receive uncached content from the server. In the event of an attack, there is a threshold from which the system disables these query parameters and only returns static pages.