DNS Glossary

Adding a domain you own to your DigitalOcean account lets you manage the domain’s DNS records with the control panel and API. Domains you manage on DigitalOcean also integrate with DigitalOcean Load Balancers and Spaces to streamline automatic SSL certificate management.

This glossary defines the core concepts behind DNS to help build your mental model of how DNS work and understand what the documentation is referring to when it uses certain terminology.

A records, or address records, map a domain name to an IPv4 address.
AAAA records, or quad A records, map a domain name to an IPv6 address.
CAA records, or Certification Authority Authorization records, or provide additional confirmation for certification authorities (CAs) to validate or issue SSL certificates for a domain.
Classless Inter-Domain Routing notation, or CIDR notation, is a method of representing an IP address network range.
CNAME records, or Canonical Name records, map an alias name to a canonical domain name.
Domain Name System management, or DNS management, is the act of managing DNS records for a particular domain or set of domains. For example, you can add an A record to a domain like example.com that points the domain to a Droplet’s IP address. This means that whenever a user types in example.com into their browser, the browser connects to Droplet’s IP and returns any websites that might be hosted there.
A DNS query is a request for information from a DNS server.
DNS records, or Domain Name System records, associate domain names map with IP addresses and other information. Common types of DNS records include A records, AAAA records, MX records, and NS records.
A DNS server, also known as a DNS resolver, is a server that contains a database of public DNS records and their associated hostnames.
MX records, or Mail Exchange records, define the mail servers responsible for accepting email on behalf of a domain.
NS records, or nameserver records, define which authoritative nameservers contain the DNS records for a domain.
PTR records, or pointer records (also known as reverse DNS or rDNS records), map an IP address to a domain name. PTR records are used for reverse DNS lookups.
SRV records, or service records, define the location (host and port) of specific services on a server. Some services, like SIP and XMPP/Jabber, require SRV records.
SSL certificate is a digital document outlining the identity of the website.
TTL, also known as time to live or hop limit, is the amount of time (also called hops) that a packet exists before being discarded by a router. TTL limits the lifespan of data within a network through attaching a time limit to data.
TXT records, or text records, define text information about sources outside of a domain. Common use cases for TXT records include creating email security records (DKIM and SPF records) and providing additional information about a domain.
Wildcard records are DNS records that direct requests for non-existent subdomains to a specified resource or IP address.