title: Must use a CNAME record to associate a domain name with RDS DB instance?
body: <p>In the <a href="https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-to-rds-db.html" rel="nofollow noreferrer">official AWS Doc for Route 53 related to RDS</a>, there is a special note of this:</p>
  
  <blockquote>
    <p>You must use a CNAME record to associate a domain name with an Amazon RDS DB instance. Route 53 doesn't support using other types of records for this purpose. </p>
  </blockquote>
  
  <p>However, I could not find an explanation of why there is such a restriction, which seems to apply to only RDS, but not to other AWS services (such as S3 or EC2).  Does anyone know why?</p>