What is DNS?

DNS stands for Domain Name System and is the system to translate friendly hostnames like example.com into the IP addresses of the server the website is hosted on. 

• A Record - An A record is a type of DNS record used for pointing the hostname to the IPV4 address (51.91.204.1).
• AAAA Record - An AAAA record is a type of DNS record used for pointing the hostname to an IPV6 address such as (2a00:1450:4009:809::200e).
• CNAME - canonical for pointing a hostname to another hostname. For example, if you want to have a sub like about.example.com. You always want it linked to the same server so you'd set up a CNAME to point to it so if you ever move then you only need to update the central a record and don't have to worry about all the different ones. For example mail.me to mail.google. Would set up as a CNAME to point to google and your config is set while google can redirect you to their changing IP. 
• NS - nameservers are DNS servers which help to resolve domains. For example at the registry would have ns1.atd. 
• MX records - defines where the email goes for particular domain name. For example, you can have multiple MX records per domain.