Content Delivery Network is a distributed network of servers designed for accelerated delivery of content to users. The CDN service aims to optimize the loading of web resources by caching pages and delivering information through the nearest server.
How CDN works and why it is important for speeding up website loading.
When accessing a website, the network directs the user's request not to the origin server but to the nearest edge server. This reduces latency, decreases the load on the main server, and speeds up content loading. Thanks to geographic server replication, data is transmitted faster, and websites operate more stably.
Main Advantages of CDN:
➤ Traffic optimization – reduces latency, lowers TTFB (Time to First Byte), improves Google PageSpeed, and enhances overall user experience.
➤ Reducing server load – redistributes requests between edge servers of the CDN, preventing the main server from being overloaded.
➤ Enhancing security – protects the site from DDoS attacks, reduces the risks of malicious requests, includes a Web Application Firewall, and ensures SSL encryption.
Thanks to these advantages, setting up a CDN becomes an indispensable tool for speeding up website performance, improving user experience, and protecting against threats.
Before configuring the content delivery network, it is important to understand what CDN configuration is and which parameters need to be considered.
How CDN works
CDN hosting is used for fast and stable content delivery by distributing data among servers around the world. The modern server architecture of a CDN reduces the load on the origin server, speeds up page loading, and ensures uninterrupted operation of the web resource by optimizing traffic handling.
Geo-Distributed server network and content caching
A Content Delivery Network is a geo-distributed network of servers that ensures high QoS (Quality of Service) by storing cached copies of both static and dynamic content. These servers are located in various regions, allowing users to load data from the nearest Point of Presence (PoP) instead of directly from the origin server.
How CDN works
A Content Delivery Network is used to efficiently distribute and reduce page load times. It acts as a reverse proxy, redirecting user requests to the nearest server to minimize latency, improve SEO optimization, and enhance user experience. Here's how it works:
➤ The user sends a request to the website.
➤ The CDN redirects the request to the nearest edge server.
➤ Content is loaded from the cache instead of requesting the main server.
➤ If the requested resource is not in the cache, the CDN server contacts the origin server, caches it, and delivers it to the user.
This server-side caching mechanism significantly reduces page load times, boosts SEO, and enhances UX through fast and stable content delivery.
Impact of CDN on speed, SEO, and user experience (UX)
Using a CDN is one of the key solutions for web acceleration, helping to minimize delays. This, in turn, positively impacts:
➤ Faster loading — reducing TTFB (Time to First Byte), improving Google PageSpeed Insights, and boosting instant page load speeds.
➤ SEO optimization — fast websites get higher rankings in search engines.
➤ Improved UX — reducing bounce rate and increasing conversions.
A CDN also enhances server-side performance, contributing to greater stability and security of web resources. Support for HTTP/2 further boosts content loading through multiplexed connections and header compression.
What types of CDN networks are there?
Companies with high requirements for speed and security may consider several options for how to build their own CDN, in order to have full control over the infrastructure. CDN networks are divided into three types, each of which has its own features and is used in different scenarios.
1. Public CDNs
These are cloud services that allow companies and website owners to use networks of local servers to cache content and deliver it quickly to users. Popular providers include:
➤ Cloudflare CDN — a free service with DDoS protection, SSL certificates, and bot filtering.
➤ AWS CloudFront — integration with Amazon Web Services, high scalability.
➤ Fastly, Akamai Technologies — enterprise solutions with advanced security features.
Such networks are widely used to speed up website loading, reduce server load, and enhance protection against cyberattacks, making them a versatile solution for businesses of any scale.
2. Private CDNs
Developed by large companies for internal use. They provide maximum performance but require significant investment in server infrastructure.
Key advantages include:
➤ Full control over traffic and security.
➤ Optimized handling of private corporate data.
These networks improve website speed and security by optimizing caching through Cloudflare CDN and Amazon CloudFront. Connecting requires configuring DNS records and HTTP/HTTPS headers, which enhances SEO and Google PageSpeed.
3. Hybrid CDNs
Combine the capabilities of public and private networks, allowing companies to balance performance, security, and cost.
Advantages include:
➤ Configuration flexibility — allows storing static content in a public network, while sensitive data is kept in private infrastructure.
➤ Speed and security optimization — improves SEO, reduces TTFB, and provides DDoS protection.
The choice of CDN type depends on project scale, budget, and data security requirements.
How to Set Up a CDN?
Configuring a CDN helps improve website loading speed, minimize network latency, and provide protection against DDoS attacks. Let’s look at the key steps on how to connect a CDN to a website.
Step 1: choosing a CDN provider
Popular providers include:
➤ Cloudflare CDN — a free CDN with attack protection.
➤ AWS CloudFront — integration with Amazon Web Services.
➤ Google Cloud CDN — ideal for cloud-based projects.
➤ Fastly, Akamai, KeyCDN — enterprise solutions.
Choosing the right CDN provider directly impacts your site’s loading speed, scalability, and security. Features like DDoS protection, Anycast routing, and geo-caching ensure efficient asset delivery and improved user experience.
Step 2: DNS and domain configuration
Proper configuration of DNS records is a crucial step to ensure correct CDN operation and accelerate content delivery. This guarantees that traffic is routed through CDN servers, which helps reduce network latency and speed up page loading. The steps include:
➤ register in the CDN provider's panel;
➤ change the domain's NS records to route traffic through the network;
➤ add CDN to Google Search Console (if needed).
After configuring DNS, it is important to verify the CDN’s functionality on the site, ensuring correct operation of SSL certificates and proper caching of all resources.
Step 3: caching and rules configuration
Configuring browser caching reduces the number of repeated requests to the server, improving load speed and decreasing the load on the origin server. Key parameters include:
➤ TTL — cache expiration settings;
➤ excluding dynamic pages from caching;
➤ clearing cache during DNS propagation.
Don’t forget to configure cache-control and HTTP headers to ensure that pages with dynamic content, such as JavaScript or CSS, are not cached and always load directly from the server.
Step 4: enabling SSL and HTTPS
Using SSL certificates not only protects data but also makes the website more trustworthy by providing secure hosting. This also helps improve SEO optimization and ensures protection against attacks, which is especially important when working with dynamic content and API integration:
➤ Cloudflare SSL — free certificates;
➤ forced redirection from HTTP → HTTPS.
Enabling SSL not only enhances security but also helps increase user trust, improving metrics such as PageSpeed Optimization and SERP ranking.
Step 5: performance optimization
How to understand CDN and improve page load times? It is important to configure performance optimization using methods like Cloudflare Railgun, code minification, and efficient image loading. These steps help improve Google PageSpeed scores, optimize HTML caching, and reduce network latency.
Key principles include:
➤ gzip compression for reducing file size;
➤ minification of CSS, JavaScript, HTML;
➤ lazy load — deferred loading of images during page scroll (image optimization).
Optimizing these aspects helps minimize requests and speed up content delivery, directly impacting SEO optimization and improving core web vitals.
How to check CDN functionality?
To verify the correct configuration and operation of the network, various tools and methods can be used. These help assess the optimization of website loading speed and identify possible issues with caching or traffic routing through CDN edge servers. You can check the CDN on a website using the following tests:
➤ Using the command line: ping, traceroute, nslookup.
➤ Google PageSpeed Insights, GTmetrix, Pingdom — speed testing.
➤ WebPageTest.org — detailed page load analysis.
Regular testing with these tools allows you to optimize cache control, verify geo-caching, and routing algorithms to improve content delivery. This helps monitor CDN health and address issues related to scalability and DDoS protection.
Common CDN configuration errors and their solutions
When setting up a CDN, various issues may arise that negatively affect website performance and cloud security. Here are some key problems and how to resolve them.
Incorrect DNS configuration → website may not load
Check the NS records: if they are configured incorrectly, traffic will not be routed through the network. To fix this, log into the CDN provider’s control panel and ensure that the domain’s NS records correctly point to the CDN servers. Errors in network configuration can cause the website to become unavailable and disrupt communication with the origin server.
Double caching → content displays incorrectly
Clarify the caching rules: double caching can occur if both the CDN and the website server try to cache the same content. To resolve this issue, configure proper cache-control headers and exclude dynamic content from being cached. This will help avoid conflicts and ensure the website functions correctly, optimizing the caching processes for JS and CSS.
SSL errors → website may show security warnings
Configure the correct SSL certificate. If your site does not use a valid SSL certificate or if there are configuration issues, users may see warnings about an insecure connection. To avoid this error, enable the free Cloudflare SSL or manually set up an SSL certificate, ensuring forced HTTP → HTTPS redirection.
It is also important to verify SSL settings at all levels, including API integration and the Web Application Firewall (WAF) for additional security.
Timely resolution of these errors helps maintain high website performance and ensures user security. Proper network configuration, TCP/IP optimization, and SSL setup improve SEO optimization, reduce TTFB, and provide reliable protection against attacks such as DDoS and Anycast.
Now we know how to identify a CDN — a key tool for speeding up site loading and protecting against attacks. It ensures fast content delivery through CDN edge servers, improving PageSpeed Optimization and minimizing network latency. Using Cloudflare CDN, Amazon CloudFront, or Fastly increases loading speed and protects against DDoS attacks.
To enable CDN, choose a provider considering scalability, SSL, caching, and DNS settings. After setup, check performance with Google PageSpeed Insights and GTmetrix.
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