From Ever changing code

This is a source of general information about Domain Name System aka DNS.

The DNS server stores different types of resource records used to resolve names, records like:

  • A - Address record - returns a 32-bit IPv4 address, most commonly used to map hostnames to an IP address of the host
  • NS - Name server record - an authoritative name server, delegates a DNS zone to use the given authoritative name servers
  • CNAME - Canonical name record - the canonical name (or Fully Qualified Domain Name) for an alias; Alias of one name to another: the DNS lookup will continue by retrying the lookup with the new name. Used when multiple services have the single network address, but each service has its own entry in DNS
  • MX - mail exchange record; maps a domain name to a list of mail exchange servers (MTA) for that domain
  • SOA - Start of [a zone of] authority record - Specifies authoritative information about a DNS zone, including the primary name server, the email of the domain administrator, the domain serial number, and several timers relating to refreshing the zone.
  • PTR - Pointer record - pointer to a canonical name. Unlike a CNAME, DNS processing stops and just the name is returned. The most common use is for implementing reverse DNS lookups

The ipconfig /displaydns command displays all of the cached DNS entries on a Windows computer system.