quartz/content/notes/dns.md

title	aliases	tags
dns		cosc203

record has four fields

• name
• value
• type
• ttl

meaning of name an value are dependent on type

Types

• A
  • name - hostname
  • value - ipv4 address for the hostname
  • hostname to ipv4 mapping
• AAAA
  • same as A but ipv6
• NS
  • name - domain (e.g., otago.ac.nz)
  • value - hostname of authoritave DNS server that knows how to get the IP address for hosts in the domain
  • used to route DNS queries further along the query chain
• CNAME
  • value - canonical hostname for the alias hostname Name
  • can provide querying the cananical name for a hostname
• MX
  • value - canonical name of a mail server that has an alias hostname name
  • allows the hostnames of mail servers to have simple aliases
  • allows a company to have the same aliased name for its mail server and for one of its other servers (e.g., web server)