Registro CNAME
Aliases one hostname to another — the resolver follows it transparently.
O que é um registro CNAME?
A CNAME (Canonical Name) record makes one hostname an alias of another. Resolvers chase the chain until they find an A/AAAA and return that. It is the standard way to point custom subdomains at CDN or PaaS hostnames (Cloudflare, Vercel, Netlify, AWS).
Exemplo de zone file
www.example.com. 300 IN CNAME example.netlify.app.
Casos de uso comuns
- ▸Point www → apex without managing IPs.
- ▸Custom domain → SaaS provider hostname (Vercel, Netlify, Heroku, GitHub Pages).
- ▸Custom CDN endpoint → CloudFront / Cloudflare / Bunny.
- ▸Service decoupling — change the upstream by editing one CNAME.
Armadilhas comuns
A CNAME at the apex breaks the rest of the zone (MX, TXT, NS, etc.). Use ALIAS / ANAME / flattening at apex. Also: never CNAME a host that itself has MX or NS records.