Simple definition
Registration DNS which creates an alias to another name DNS.
Technical definition
Registration DNS which creates an alias to another name DNS. In a professional environment, this mechanism usually integrates with other services to point a user-friendly name to a target name managed elsewhere.
What is it used for?
point a user-friendly name to a target name managed elsewhere.
Practical example
www.exemple.fr is a CNAME to a hosting platform.
Common issues
- missing or incorrect recording
- cache DNS still active
- Incoherent delegation or authoritative server
Key takeaway: Always adapt the diagnosis to the product version and the architecture actually deployed.