What is a CDN and Why Your Website Needs One

In today’s digital world, users expect websites and apps to load in the blink of an eye. Whether you’re running a personal blog or managing a large-scale e-commerce platform, delivering content quickly and reliably is critical to user experience and SEO performance. This is where a CDN — or Content Delivery Network — comes into play.
A Content Delivery Network (CDN) is a geographically distributed network of servers designed to deliver web content — such as HTML pages, JavaScript files, stylesheets, images, and videos — to users with high availability and performance.
Instead of relying on a single server (which could be halfway around the world from some of your users), a CDN stores cached versions of your content on edge servers located in multiple data centers across the globe.
When a user accesses your site, the CDN intelligently routes their request to the server closest to them geographically, ensuring faster load times and a smoother experience.

Understanding CDN with a YoYo Business Example

Let’s say you’ve started a small business making high-tech yoyos at your home in Sydney, Australia. At first, you ship them locally, and everything works smoothly. But soon, you notice a growing demand from customers in North America.
Now, shipping each yoyo from Sydney to North America takes time and costs more. To speed things up and improve customer satisfaction, you decide to send a big batch of yoyos to your friend who lives in the U.S. So whenever someone from North America places an order, your friend can ship it directly — it’s faster and cheaper.
That’s exactly how a CDN (Content Delivery Network) works.

Instead of sending every request to the original server (your home in Sydney), the CDN stores your static content (like images, videos, and files) on servers located closer to your users (like your friend’s house in North America). When a user visits your website, the CDN serves the content from the nearest location, making the site load much faster.
The content stays cached there until it either expires based on a set time (TTL — Time to Live) or is manually cleared by you.

Popular CDN providers

There are many CDN services available, ranging from free to enterprise-grade solutions. Some of the most popular ones include:

• Cloudflare – Popular for both security and performance, with a generous free plan.
• Amazon CloudFront – AWS’s CDN, great for deep cloud integrations.
• Akamai – One of the oldest and most extensive CDN providers.
• Google Cloud CDN – Integrated with Google Cloud services.
• Fastly – Known for real-time caching and developer-friendly tools.

Step-by-Step Guide: Integrating CloudFront with an AWS Load Balancer

Prerequisite

    add_header Cache-Control "public, max-age=86400";
                    

    server {
        listen       80;
        listen       [::]:80;
        server_name  _;
        root         /usr/share/nginx/html;
    
        # Load configuration files for the default server block.
        include /etc/nginx/default.d/*.conf;
    
    
        location / {
        root /usr/share/nginx/html;
        add_header Cache-Control "public, max-age=86400";
        }
    }
            

Why Cache-Control Matters

• Without an explicit Cache-Control, CloudFront doesn’t know:
• How long it should store the content (max-age)
• If it’s safe to cache the response (public vs private)
• Whether it’s allowed to serve stale content

• Use its default TTL, if you’ve set one in the cache policy
• Otherwise, may decide not to cache (especially for HTML)

When Cloudfront Caches by Default

Steps to Setup Cloudfront Distribution

1. In the AWS Console, search for CloudFront, then click on Create a CloudFront distribution.
2. Provide a name. For simplicity, choose “Single website or app” under the distribution option, then click Next.
3. Here, CloudFront offers different origin sources — we’ll use Elastic Load Balancer.
4. Under Origin, browse existing load balancers, select yours, and click Next.
5. Select Custom origin settings, and choose HTTP only under the protocol (since our target listens on port 80). and click on next You can learn more about origin settings [here] .



6. On the next page, you’ll see security settings where you can enable WAF within CloudFront. Learn more about CloudFront and WAF [here] .
   For now, select “Do not enable security protection” and click Next.



Click on Create Distribution

Once created, you’ll see the Last modified state. If it's deploying, wait for a few minutes.

You can now access the web server using the distribution domain name.

Check the response headers — CloudFront adds extra headers that indicate cache behavior.
One important header is x-cache, which shows whether the content is served from an edge location or the origin server.

For the first request, you'll see:

Miss from CloudFront – meaning the response is coming from the origin.



If you perform a hard reload or open the site in a private/incognito window,

you'll see the following in the response headers:

Hit from CloudFront

This indicates that the content is being served from the edge location, not the origin server.



This indicates that the content is served from the edge location instead of the origin server.

Adding a Alternate Domain Name

1. Search for Certificate Manager in the AWS Console and click on Request a certificate.
2. Choose Request a public certificate under Certificate Type, then click Next.
3. In Fully qualified domain name, enter the DNS name you want to use with your CloudFront distribution.
4. Leave the remaining settings as default and click Request.
5. Under the Domains section, a CNAME entry will be provided. Add this to your DNS records for verification.
6. Create a DNS record of type CNAME using the provided name and value.
7. Wait a few minutes until the status changes to Success.

1. Type the full domain name you want to use.
2. Click on Next and select the certificate you created in Certificate Manager.
3. Click Next again and then Add domain.

Conclusion

This is a simple example of how we can use CloudFront to serve our content from AWS edge locations.

For larger files or high-traffic applications, this approach significantly improves performance and reduces latency.

It not only enhances user experience but also helps offload traffic from your origin server.

CloudFront also offers features like caching, security integration with WAF, and support for custom domains — making it a powerful choice for content delivery.

Further Reading / References

• Amazon Cloudfront Documentation
• Accelerate and protect your websites using Amazon CloudFront and AWS WAF
• Add, remove, or replace content that CloudFront distributes
• You can modify the cache behaviour for which you can refer:
  • Control the cache key with a policy
  • Control origin requests with a policy

Cleanup

• Disable and delete the CloudFront distribution.
• Delete the certificate from Certificate Manager.
• Remove the DNS records you created.
• Delete the server, load balancer, and target group.