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DNS¶

The Domain Name System (DNS) is the phonebook of the Internet. Humans access information online through domain names, like geekfa.net or espn.com. Web browsers interact through Internet Protocol (IP) addresses. DNS translates domain names to IP addresses so browsers can load Internet resources.

See the all types of DNS servers

DNS record¶

DNS records (aka zone files) are instructions that live in authoritative DNS servers and provide information about a domain including what IP address is associated with that domain and how to handle requests for that domain. These records consist of a series of text files written in what is known as DNS syntax. DNS syntax is just a string of characters used as commands that tell the DNS server what to do. All DNS records also have a ‘TTL’, which stands for time-to-live, and indicates how often a DNS server will refresh that record.

  • A record - The record that holds the IP address of a domain.
  • AAAA record - The record that contains the IPv6 address for a domain (as opposed to A records, which list the IPv4 address).
  • CNAME record - Forwards one domain or subdomain to another domain, does NOT provide an IP address
  • MX record - Directs mail to an email server.
  • TXT record - Lets an admin store text notes in the record. These records are often used for email security.
  • NS record - Stores the name server for a DNS entry.
  • SOA record - Stores admin information about a domain.
  • SRV record - Specifies a port for specific services.
  • PTR record - Provides a domain name in reverse-lookups.
  • CERT record - The ‘certificate record’ stores public key certificates.

  • CAA record - This is the ‘certification authority authorization’ record, it allows domain owners state which certificate authorities can issue certificates for that domain. If no CAA record exists, then anyone can issue a certificate for the domain. These records are also inherited by subdomains.

  • IPSECKEY record - The ‘IPSEC key’ record works with the Internet Protocol Security (IPSEC), an end-to-end security protocol framework and part of the Internet Protocol Suite (TCP/IP).

  • LOC record - The ‘location’ record contains geographical information for a domain in the form of longitude and latitude coordinates.
  • SSHFP record - This record stores the ‘SSH public key fingerprints’; SSH stands for Secure Shell and it’s a cryptographic networking protocol for secure communication over an unsecure network.