What is DNS
1.
To get to www.example.com, your computer needs to know where on the Internet that server is
That means: it has to know what IP address to talk to
The way it finds out is the Domain Name System (DNS)
2.
When you register a domain, you can set many types of DNS Records
Each record has a Type, a Host, and a Value
- “Types” are predefined
- “Host” represents the root (@) or a subdomain (www)
- “Value” is an IP or web address, or other value
3.
The A record maps a subdomain to an IPv4 address
This is most commonly used at the root, so it tells your browser where example.com lives
The AAAA record does the same for IPv6
cheat sheet
But there’s a problem with CNAME!
Once you define a CNAME record for a subdomain (host), you CAN’T DEFINE another record for that same subdomain
Because of this, you can’t use CNAME at the root level (where you need other records to exist)
