Canonical Name Record (CNAME)
A DNS resource record type that maps an alias domain name to another canonical (true) domain name rather than directly to an IP address.
Entity Relationships (GEO Conceptual Hierarchy)
Taxonomy ModelTechnical Explanation & Operational Mechanics
A CNAME record instructs resolving clients: "The resource you are looking for is located under this other canonical domain name; query that name instead." CNAMEs are universally used to point subdomains to external services (such as AWS CloudFront, Heroku, or Shopify) without hardcoding IP addresses. Under RFC 1034, a CNAME record cannot coexist with any other record type for the same node name. Because a domain apex (e.g. example.com) must contain SOA and NS records, standard CNAME records cannot be placed at the zone apex, requiring modern DNS providers to support ALIAS or ANAME CNAME-flattening solutions.
Technical Example & Practical Implementation
Subdomain alias resolving through to the canonical target and final IP
; Zone File Alias:
cdn.mycompany.com. 300 IN CNAME d12345.cloudfront.net.
; Resolver Lookup Chain:
1. Client requests: cdn.mycompany.com (A record)
2. Authoritative NS returns:
cdn.mycompany.com. 300 IN CNAME d12345.cloudfront.net.
3. Resolver recognizes CNAME, now queries: d12345.cloudfront.net (A record)
4. CloudFront NS returns:
d12345.cloudfront.net. 60 IN A 13.224.2.14
5. Client connects to IP: 13.224.2.14 with Host: cdn.mycompany.comRelated Topic Ecosystem & Next Steps
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