DNS#

Domain name system, the process for resolving domain names to IP addresses.

In the public space, this resolution goes through a chain.

To access mail.github.com for example

  • Device queries the configured DNS server by IP

  • This server queries the RootDNS servers for the IP of the appropriate TLD server (in this case .com)

  • Once it has the IP of the TLD server, It asks the TLD server for the IP address of the domain authorative server (in this case, github.com)

  • Lastly the server can now ask the domain authorative server for the subdomain IP (in this case, mail.github.com)

  • This final IP address is then passed back to the host and cached in the DNS server

Record types#

  • A: IPv4 Address

  • AAAA: IPv6 Address

  • MX: Mail Record

  • NS: Authorative Name Server