How to: Using CDNs - Complete Guide to Content Delivery Networks

Posted on December 15, 2022

Content Delivery Networks (CDNs) are becoming the norm for many web-based applications, but too often the benefits of CDNs go unnoticed. If you're looking to increase speed and reduce bandwidth, a CDN can be your solution. This comprehensive guide will provide you with all the information you need to get started using a CDN, including when it makes sense to use one and how they compare to other options.

What is a CDN?

Content Delivery Networks (CDNs) are an important part of many online businesses today. They provide a reliable way to store and deliver content quickly and securely.

How does a CDN work?

CDNs are networks of geographically dispersed servers that store copies of your website’s content, such as images, videos, HTML files, and JavaScript libraries. When a user requests content from your website, the request is routed to the nearest server in the CDN network so it can be delivered faster than if it were requested from a server located farther away. This helps reduce page loading times for users around the world who may not be close enough to your primary server locations.

Does my website need a CDN?

It is very difficult to answer this question with a "yes" or "no". It depends on many factors, such as your website popularity and what kind of audience it has. This article will teach you how CDNs works and the benefits and drawbacks of using them. The final decision is always yours.

Types of CDN Services

There are a variety of different services that can be offered by CDNs, and it’s important to understand the options available. Here are the most common services:

  • Content Cache: This service stores the most popular static content from your website on the CDN’s servers, eliminating the need for your visitors to load the content from your own server each time they click on a link. Loading your website static content closer to the end user will vastly improve the loading speed.
  • Load Balancing: When your origin server is overwhelmed by requests, the CDN helps to distribute the load by sending the requests to other servers. All major CDN providers have multiple points of presence worldwide and can reroute traffic to the most appropriate location.This helps to prevent downtime and outages.
  • SSL/TLS Offload: This helps to reduce server load by allowing the CDN to encrypt the connection.
  • Media Streaming: This service provides streaming media services that allow users to download and upload streaming content such as video or audio from a nearest CDN server.

Benefits of Using a CDN

Here are some of the most important benefits of using a CDN:

Speed and reliability

Having your content delivered quickly and reliably is critical to providing an optimal user experience. With a CDN, your content is cached on servers around the world and served to users based on where they're located. This helps to increase website speed and reliability.

Improved Security

CDN technology is designed to protect your content from malicious attacks. With a global distributed system of servers, there are many layers of protection in place that help to prevent security breaches.

It can also protect you against a DDoS attack. CDNs can spread out traffic over numerous servers, aiding in absorbing a DDoS attack to avoid overloading a single server. Additionally, CDNs can employ techniques such as caching and rate limiting to reduce the damage of a such an attack.

Cost savings

Implementing a CDN can help reduce hosting costs by offloading content delivery from your own servers.

Global Reach

A CDN helps you to reach a much broader audience around the world. With a global network of servers, your content can be delivered to users wherever they are.


With a CDN, you're able to easily scale your website or application as needed. With a larger global network and more cache points, your website can handle massive traffic spikes and still remain responsive.


A CDN gives you more control and flexibility over how you deliver your content to different regions. With options to customize settings, you can ensure your content is delivered the best way to each region and user.

How to choose a CDN

The provider should have the ability to handle the type of traffic you expect. It should also support the specific content types you plan to deliver. Make sure the platform is reliable and secure and check out the associated costs.

Choosing a best CDN can be a difficult choice. Here are some quality CDNs from industry leaders to choose from:

  • Akamai: More than 200,000 servers in over 1,500 cities.
  • Amazon CloudFront: Offered by Amazon Web Services (AWS), with a global network of edge locations.
  • Cloudflare: More than 200 data centers in over 100 countries.
  • Fastly: A global network of edge servers in more than 70 cities.
  • Google Cloud CDN: A service offered by Google Cloud Platform (GCP).
  • Microsoft Azure CDN: Offered by Microsoft Azure Cloud.
  • StackPath: A network of over 50 data centers.
  • CDNetworks: A network of over 200,000 servers.

This is by no means a complete list and we recommend you to do your own research.

How to setup and use a Content Delivery Network

Setting up your own CDN is easier than you might think. Here's how to get started:

Set up your DNS records

This can vary depending on your provider, but in most cases you'll need to create a unique subdomain for your DNS records. This will help direct traffic to the right CDN.

Configure your CDN settings

It's important to customise the settings of your CDN to make sure it's correctly configured and optimized for your needs. You will have to follow the following steps:

  • Choose the type of content to be delivered by the CDN, e.g. images, videos or JavaScript files.
  • Create a procedure for uploading the static content to the CDN, either through the service provider's web-based interface or with a command-line tool.
  • Alter the HTML code of the website to point to the static content hosted on the CDN.
  • Check the website to guarantee the CDN is correctly serving the content.

Monitor the performance of your CDN

You should make sure to track the performance of your CDN over time. Your provider should provide analytics tools to help you track how your content is being delivered and whether your rules are working correctly.

We also recommend to use an external monitoring service, such as Uptimia, to monitor the performance of your CDN.

Troubleshooting Common CDN Issues

Now, let’s look at some of the common CDN problems you might encounter and how to troubleshoot them.

CDN Timing Out

Is your CDN timing out? This could be due to a few things. If you’re working with CDN caching, it could be that the TTL (time-to-live) of your CDN is too low, or that your origin server is sending cached information that has expired or is no longer needed. It could also be a problem with your CDN caching cores, such as too many requests or too little RAM allocated for caching.

To fix this, you first need to check the TTL values set on your CDN and make sure they are properly configured. You’ll also want to check your own server to make sure all of the cached information is up to date. Finally, make sure that your CDN caching cores are properly configured in terms of RAM and request handling.

Slow CDN Performance

If your CDN is performing slowly, it could be caused by a few different things. It could be due to a lack of bandwidth on your CDN provider’s network, latency issues, or even a congested route between the CDN service provider and your website server.

To figure out the issue, start by running a traceroute from your origin server to your CDN provider and look for any latency or packet loss problems. Then, check your CDN service provider to make sure there is enough bandwidth to handle your traffic. Finally, if you have a congested route between your CDN provider and origin server, you’ll need to look for ways to improve your connection.

Poor CDN Uptime

If your CDN’s uptime is suffering, there could be several causes. This could be due to a misconfigured DNS record, unresponsive origin server, or even poor performance on the provider’s side.

To figure out the cause, start by checking your DNS records to make sure they are properly configured. Then, check your origin server to make sure it is running smoothly and responding to requests. Finally, make sure the CDN service provider is able to handle your traffic and requests.

We recommend you to monitor the uptime of your CDN service by using Uptimia. You can easily setup a monitoring check with our Uptime Monitoring Tool to monitor if, for example, "" is always available. You can forward an outage report to your CDN service provider in case we detect an outage.

By following these troubleshooting tips, you can normally get to the root of the problem and find a solution quickly and easily. Whether you’re experiencing slow performance, timing out, or poor uptime with your CDN, these tips will help you diagnose and fix the issue.

Drawbacks of CDNs

As with anything, relying on a CDN (Content Delivery Network) has its drawbacks. They should be taken into account when deciding whether or not to use one.

High Costs

CDNs are not cheap and the costs can quickly add up. Depending on the size of your website and the amount of traffic it receives, the cost of using a CDN can become quite high. Additionally, some CDNs require monthly fees and contracts, which can make them even more expensive.

Complicated Setup

Setting up a CDN can be complicated and time-consuming. It requires knowledge of server configuration and the ability to set up DNS records. Additionally, if the CDN is not configured correctly, it can cause performance issues.

Data Loss

CDNs are not designed to store content and data, so if the service goes down or experiences outages, the data stored on the CDN can be lost.

Lack of Control

With a Content Delivery Network, you have less control over the content being served and how the content is delivered. The service provider may have rules and policies that you must adhere to, which can limit your ability to customize the content delivery.


A CDN can help to improve website performance, speed up content delivery, and improve security. Taking the time to understand how to use a content delivery network and the different services available can help you to take full advantage of their benefits.