CNAME Record

Points to a domain name, which then resolves to the resource.

www.mysite.com -> elb-123.amazonaws.com -> (DNS resolves) -> 54.123.45.67

Two steps. CNAME just points to another name, not directly to IP.

www.mysite.com  -> elb-123.amazonaws.com
blog.mysite.com -> myblog.wordpress.com
app.mysite.com  -> external-app.com

Rules

• Only works on subdomains, never root domain
• Works with both AWS and non-AWS resources
• You pay for every DNS query

When to Use

• Pointing subdomains to any external service
• Need to point to non-AWS resources

Alias Record

AWS-specific record that points directly to AWS resources.

Points directly to the AWS resource itself, Route 53 handles the IP internally.

mysite.com -> Alias -> Load Balancer (Route 53 knows the IP automatically)

One step. No extra DNS lookup needed.

mysite.com     -> Application Load Balancer
mysite.com     -> CloudFront
api.mysite.com -> API Gateway

Rules