quartz/content/notes/dns.md
2022-09-22 20:19:34 +12:00

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Markdown

---
title: "dns"
aliases:
tags:
- 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)
-