cname vs alias

cname

• “A” maps a name to an IP address (eg cat.io maps to 1.3.3.7)
• CNAME maps a NAME to another NAME (www.cat.io ⇒ cat.io), create alternative name for something within DNS
• However, CNAME is invalid for naked domain (cannot cat.io⇒ www.cat.io)
• many AWS services use a DNS name, cannot point to a CNAME

alias

• only used when route 53 hosting the domain, it is not a DNS standard
• ALIAS records map a name to an AWS resource
• can be used both for naked and normal records
• For AWS services - default to picking ALIS