The DNS name server holds the correspondence bewteen domain names and host names and IP addresses as a databases. The data processed by this database is called a “resource record”.

The structure and format of this database and resource record depend on the DNS server. The most famous DNS server software “BIND” holds a database called “zone file” as a text file. In BIND, resource records such as correspondence between host name and IP addresses are described in zone files.

– A
– MX (mail exchange)
– NS (name server)
– SOA (start of authority)

The correspondence bewteen domain names and IP addresses does not have to be one to one. Multiple IP addresses can be associated with one domain name. In this case, plurality of IP addresses will be described in one A record.

AWS Route 53

AWSの場合、Aレコードがipアドレスではありませんね。Name Serverも.org, .net, co.uk, comの4つが登録されています。