Why Is My CDN Not Respecting Cache Headers? Troubleshooting Guide

Content Delivery Networks (CDNs) are essential for improving website speed, reliability, and security by distributing cached content across global edge servers. However, one common issue website owners face is that their CDN does not seem to respect cache headers, leading to stale content, increased load times, or unexpected behavior.

If you’re experiencing this issue, it can be frustrating—especially if your website relies on cloud hosting solutions like Cyfuture Cloud or other performance optimization techniques. This guide will help you understand why your CDN may not be respecting cache headers and how to troubleshoot the issue effectively.

Understanding Cache Headers & CDN Caching Behavior

Cache headers are instructions that tell browsers and CDNs how to store and serve content efficiently. The two main types of cache headers are:

Cache-Control: Defines caching policies, such as how long an asset should be stored before revalidation.

Expires: Sets a specific expiration date for cached content.

ETag (Entity Tag): Helps browsers and CDNs determine whether content has changed.

Last-Modified: Indicates when the resource was last updated.

CDNs work by storing static content (HTML, CSS, JavaScript, images, etc.) on their global servers to reduce latency. If your CDN isn’t respecting your cache headers, it means it may be ignoring your cache rules and fetching fresh content more often than needed (or vice versa, serving outdated content).

Common Reasons Why a CDN Ignores Cache Headers

1. Default CDN Caching Policies Override Your Headers

Many CDN providers have default caching policies that override your website’s cache headers. For example:

Some CDNs enforce a minimum TTL (Time-To-Live), preventing short expiration times.

Others may ignore no-cache or no-store directives for performance reasons.

Solution:

Check your CDN’s cache settings and ensure they allow for custom cache rules.

On platforms like Cyfuture Cloud, you can adjust cache settings to respect origin server headers.

2. Your Cache-Control Header Is Misconfigured

If your Cache-Control directives are set incorrectly, the CDN may not cache content as expected.

Examples of Common Misconfigurations:

Cache-Control: no-cache – Forces revalidation but doesn’t prevent caching.

Cache-Control: no-store – Prevents any caching (even on browsers).

Cache-Control: max-age=0, must-revalidate – Ensures fresh content but may cause unnecessary CDN requests.

Solution:

Use Cache-Control: public, max-age=86400 (for one-day caching) for assets that don’t change often.

Set Cache-Control: private, no-store for sensitive data that shouldn’t be cached.

3. The CDN Is Not Forwarding Cache Headers Correctly

Some CDNs may strip, modify, or not forward cache headers properly between the origin server and the end user.

Solution:

Check your CDN configuration to see if cache headers are being passed correctly.

In platforms like Cyfuture Cloud, enable “Forward Headers” to ensure cache policies are respected.

4. Origin Server Rules Conflict with CDN Cache Settings

If your server settings contradict your CDN cache rules, the CDN might not follow cache headers properly.

Example Conflict:

Your origin server has Cache-Control: max-age=3600, but the CDN has a rule forcing max-age=86400.

Your origin sends Expires: 0, but the CDN enforces its own expiration policies.

Solution:

Ensure your CDN’s cache settings match your origin server policies.

Modify your origin server’s headers to align with your desired caching behavior.

5. Dynamic Content Being Served Instead of Cached Files

Some CDNs bypass caching for dynamic content, leading to frequent re-fetching from the origin server.

Solution:

Enable full-page caching for pages that don’t change often.

Use Edge Side Includes (ESI) to cache parts of a page while keeping dynamic elements fresh.

6. Cookies and Query Parameters Are Preventing Caching

Certain CDNs avoid caching pages with query parameters or session cookies, as they assume each request is unique.

Solution:

Configure your CDN to ignore unnecessary query parameters.

Use cookie-free domains for static content (images, CSS, JavaScript).

7. Incorrect Cache Purge or Stale Content Issues

If your CDN serves outdated content even after updates, it may be due to stale cache policies or improper cache purging.

Solution:

Manually purge the cache from your CDN’s dashboard.

Set Cache-Control: stale-while-revalidate to allow fresh content updates while serving stale cache temporarily.

How to Verify If Your CDN Is Respecting Cache Headers

To check whether your CDN is following your cache headers, use these tools:

1. Browser Developer Tools (Chrome, Firefox, Edge)

Open DevTools (F12 or Ctrl+Shift+I on Windows, Cmd+Option+I on Mac).

Navigate to the Network tab and refresh the page.

Click on a request and look at the Response Headers (especially Cache-Control, Expires, and ETag).

2. CURL Command-Line Tool

Run the following command to check headers:

curl -I https://yourwebsite.com

Look for:

Cache-Control: max-age=86400, public

Expires: Wed, 29 Mar 2025 12:00:00 GMT

3. Online Tools

CDN Performance Checkers – Services like GTmetrix and Pingdom show how your CDN is caching content.

Cyfuture Cloud CDN Analysis Tool – Helps users check real-time cache behaviour.

Best Practices for CDN Caching Optimization

Set a Proper Cache Hierarchy – Use different TTLs for different content types (e.g., images = longer cache, HTML = shorter cache).

Utilize Stale-While-Revalidate – Reduces cache misses while serving slightly older content.

Enable Cache Logging & Reports – Monitor how your CDN handles requests.

Use Versioning for Static Assets – Append query strings (?v=1.2) to force updates without excessive cache purging.

Work With a Reliable CDN Provider – CDNs like Cyfuture Cloud offer customizable caching rules that respect origin cache headers.

Conclusion

If your CDN isn’t respecting cache headers, it could be due to default caching policies, misconfigured headers, conflicts between origin settings, or dynamic content handling. By carefully analyzing your cache settings, using debugging tools, and adjusting CDN policies, you can ensure optimal caching behaviour.

For businesses using cloud hosting and CDN services, working with a trusted provider like Cyfuture Cloud allows for better control over cache settings, faster load times, and improved website performance. Whether you’re managing a high-traffic eCommerce site or a dynamic web application, proper caching ensures a seamless user experience and reduces server load.

If troubleshooting doesn’t resolve your issue, contact your CDN support team for further assistance and custom caching configurations.