Skip to content

AWS Solutions Architect Associate (SAA-C02)


  • Global service
  • Global Content Delivery Network (CDN)
  • Edge Locations are present outside the VPC so the origin's SG must be configured to allow inbound requests from the list of public IPs of all the edge locations.
  • Supports HTTP/RTMP protocol (does not support UDP protocol)
  • Caches content at edge locations, reducing load at the origin
  • Geo Restriction feature
  • Improves performance for both cacheable content (such as images and videos) and dynamic content (such as API acceleration and dynamic site delivery)
  • To block a specific IP at the CloudFront level, deploy a WAF on CloudFront
  • Supports Server Name Indication (SNI) to allow SSL traffic to multiple domains


  • S3 Bucket
    • For distributing static files
    • Origin Access Identity (OAl) or Origin Access Control (OAC) allows the S3 bucket to only be accessed by CloudFront
    • Can be used as ingress to upload files to S3
  • Custom Origin (for HTTP) - need to be publicly accessible on HTTP by public IPs of edge locations
    • EC2 Instance
    • ELB
    • S3 Website (may contain client-side script)
    • On-premise backend

To restrict access to ELB directly when it is being used as the origin in a CloudFront distribution, create a VPC Security Group for the ELB and use AWS Lambda to automatically update the CloudFront internal service IP addresses when they change.

Signed URL / Cookies

  • Used to make a CloudFront distribution private (distribute to a subset of users)
  • Signed URL ⇒ access to individual files
  • Signed Cookies ⇒ access to multiple files
  • Whenever we create a signed URL / cookie, we attach a policy specifying:
    • URL / Cookie Expiration (TTL)
    • IP ranges allowed to access the data
    • Trusted signers (which AWS accounts can create signed URLs)


  • Price Class All: all regions (best performance)
  • Price Class 200: most regions (excludes the most expensive regions)
  • Price Class 100: only the least expensive regions

Multiple Origin

  • Route to different origins based on the path in the request
    • attachments/Pasted image 20220508161137.jpg

Origin Groups

  • Consists of a primary and a secondary origin (can be in different regions)
  • Automatic failover to secondary
    • attachments/Pasted image 20220508161659.jpg
  • Provides region-level High Availability
  • Use when getting 504 (gateway timeout) Error

Field-level Encryption

  • Sensitive information sent by the user is encrypted at the edge close to user which can only be decrypted by the web server (intermediate services can't see the encrypted fields)
  • Asymmetric Encryption (public & private key)
  • Max 10 encrypted field

Last updated: 2023-02-15