Some Q/A for DNS

Q: What is DNS?
A: Domain Name System (DNS) is a core service of Internet. It can be used as a distributed database in which the domain name and the IP address can be mapped to each other. Currently, the open-source software bind is used in mainstream DNS servers.

Q: What are the A record and CNAME record on DNS?
A: A (Address) record is used to specify an IP address record corresponding to a host name (or a domain name).
    A CNAME record, i.e. a canonical name record, allows you to map multiple names onto the same computer. Generally, it is used on computers that provide both www and mail services.

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