Quick Answer First

CNAME Record

Points to a domain name, which then resolves to a 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 an IP.

Examples

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 (WordPress, external APIs, etc.)

Alias Record

AWS-specific record. Points directly to an AWS resource — Route 53 handles the IP internally.

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