AWS CloudFront DNS: Removing S3 Links

Amazon Web Services (AWS) offers a powerful suite of services for content delivery and storage. Amazon S3 is a highly scalable object storage service, while AWS CloudFront is a content delivery network (CDN) service. In many scenarios, developers and system administrators want to use CloudFront in front of S3 to enhance performance, security, and user experience. One important aspect in this setup is the ability to remove S3 links from the DNS configuration, ensuring that end - users only interact with the CloudFront domain. This blog post will explore the core concepts, typical usage scenarios, common practices, and best practices related to removing S3 links in the AWS CloudFront DNS setup.

Table of Contents#

  1. Core Concepts
    • AWS S3
    • AWS CloudFront
    • DNS and Link Removal
  2. Typical Usage Scenarios
    • Security Enhancement
    • Performance Improvement
    • Branding and User Experience
  3. Common Practice
    • Setting up CloudFront with S3
    • Configuring DNS to Point to CloudFront
    • Removing S3 Links
  4. Best Practices
    • Cache Management
    • Monitoring and Logging
    • Security Configuration
  5. Conclusion
  6. FAQ
  7. References

Article#

Core Concepts#

AWS S3#

Amazon S3 is an object storage service that provides industry - leading scalability, data availability, security, and performance. It allows users to store and retrieve any amount of data at any time, from anywhere on the web. Each object in S3 is stored in a bucket, and it has a unique URL that can be used to access the object directly.

AWS CloudFront#

AWS CloudFront is a CDN service that securely delivers data, videos, applications, and APIs to customers globally with low latency and high transfer speeds. It caches content at edge locations around the world, reducing the distance between the end - user and the content source. When using CloudFront with S3, CloudFront can act as a proxy between the end - user and the S3 bucket, fetching content from S3 and serving it to the user.

Domain Name System (DNS) is the system that translates human - readable domain names (e.g., example.com) into IP addresses. When using CloudFront in front of S3, we want to configure DNS so that end - users access the content through the CloudFront domain rather than the S3 domain. Removing S3 links from the DNS configuration means ensuring that there are no direct references to the S3 bucket URLs in the DNS records, preventing users from bypassing CloudFront and accessing the S3 bucket directly.

Typical Usage Scenarios#

Security Enhancement#

Direct access to an S3 bucket can pose security risks. By removing S3 links from the DNS, we ensure that all traffic goes through CloudFront. CloudFront provides security features such as AWS WAF (Web Application Firewall) integration, which can protect against common web - based attacks like SQL injection and cross - site scripting (XSS).

Performance Improvement#

CloudFront caches content at edge locations close to the end - users. When users access content through CloudFront, they can experience lower latency and higher transfer speeds compared to accessing the S3 bucket directly. Removing S3 links ensures that users always benefit from CloudFront's caching and delivery capabilities.

Branding and User Experience#

Using a custom domain for CloudFront can enhance the branding of the application or website. End - users will see a consistent domain name, which improves the overall user experience. For example, instead of seeing an S3 URL like https://my - bucket.s3.amazonaws.com/image.jpg, users will see https://cdn.example.com/image.jpg.

Common Practice#

Setting up CloudFront with S3#

  1. Create a CloudFront distribution: In the AWS Management Console, navigate to the CloudFront service and create a new distribution. Select the S3 bucket as the origin.
  2. Configure the origin settings: Specify the S3 bucket name and configure other settings such as origin access identity (OAI). An OAI allows CloudFront to access the S3 bucket on behalf of the end - users.
  3. Set up cache behavior: Define how CloudFront caches and serves the content. You can configure cache expiration times, query string forwarding, etc.

Configuring DNS to Point to CloudFront#

  1. Get the CloudFront domain name: After creating the CloudFront distribution, note down the domain name provided by CloudFront (e.g., d1234567890abc.cloudfront.net).
  2. Create DNS records: In your DNS management console (e.g., Route 53 if you are using AWS), create a CNAME or an alias record that points your custom domain (e.g., cdn.example.com) to the CloudFront domain name.
  1. Update application code: If your application code references S3 bucket URLs directly, update them to use the CloudFront domain instead.
  2. Check existing DNS records: Make sure there are no DNS records that point directly to the S3 bucket. Delete any such records if found.

Best Practices#

Cache Management#

  • Set appropriate cache expiration times: Determine the optimal cache expiration times based on the nature of your content. For static content like images and CSS files, longer cache expiration times can be set to reduce the number of requests to the origin.
  • Invalidate the cache when necessary: If you update the content in the S3 bucket, you may need to invalidate the cache in CloudFront to ensure that users see the latest version of the content.

Monitoring and Logging#

  • Enable CloudFront logs: CloudFront provides access logs that can be used to monitor the traffic, cache hits, and cache misses. Analyzing these logs can help you optimize your CloudFront configuration.
  • Set up AWS CloudWatch metrics: Monitor CloudFront - related metrics such as requests, bytes transferred, and error rates in CloudWatch. Set up alarms to notify you of any abnormal behavior.

Security Configuration#

  • Enable AWS WAF: Integrate AWS WAF with your CloudFront distribution to protect against common web - based attacks.
  • Use secure protocols: Ensure that your CloudFront distribution uses HTTPS to encrypt the data in transit between the end - user and CloudFront.

Conclusion#

Removing S3 links from the DNS configuration when using AWS CloudFront with S3 is an important step for enhancing security, improving performance, and providing a better user experience. By understanding the core concepts, typical usage scenarios, common practices, and best practices, software engineers can effectively set up and manage their CloudFront - S3 infrastructure. This setup ensures that end - users interact with the content through the CloudFront domain, leveraging its caching and delivery capabilities while maintaining a high level of security.

FAQ#

A: Yes, it is still possible to access the S3 bucket directly if you know the S3 bucket URL. However, by configuring appropriate bucket policies and using an origin access identity (OAI) with CloudFront, you can restrict direct access to the S3 bucket.

Q: How long does it take for DNS changes to propagate?#

A: DNS propagation times can vary, but it usually takes between 15 minutes to 48 hours for the changes to propagate globally. In some cases, it may be faster, especially if your DNS provider has a large network of name servers.

Q: What if I need to update the content in the S3 bucket frequently?#

A: If you need to update the content frequently, you can set shorter cache expiration times in CloudFront or invalidate the cache manually after each update. This ensures that users see the latest version of the content.

References#

2025-10