DNS records

2 years ago
SeekaHost Writer
4 minutes

What is a 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. That listing will give you helpful information about a business, such as its location, hours, services, etc. All domains must have at least a few essential DNS records for a user to access their website using a domain name, and several optional records serve additional purposes.

Common types of DNS records.

 

  • 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 – Let 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.

Less common types of DNS records.

 

  • AFSDB record – This record is used for clients of the Andrew File System (AFS) developed by Carnegie Melon. The AFSDB record functions to find other AFS cells.
  • APL record – The ‘address prefix list’ is an experiment record that specifies lists of address ranges.
  • 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.
  • DNSKEY record – The ‘DNS Key Record’ contains a public key used to verify Domain Name System Security Extension (DNSSEC) signatures.
  • CDNSKEY record – This is a child copy of the DNSKEY record, meant to be transferred to a parent.
  • CERT record – The ‘certificate record’ stores public key certificates.
  • DCHID record – The ‘DHCP Identifier’ stores info for the Dynamic Host Configuration Protocol (DHCP), a standardized network protocol used on IP networks.
  • DNAME record – The ‘delegation name’ record creates a domain alias, just like CNAME, but this alias will also redirect all subdomains. For instance, if the owner of ‘example.com’ bought the domain ‘website.net’ and gave it a DNAME record that points to ‘example.com’, then that pointer would also extend to ‘blog.website.net’ and any other subdomains.
  • HIP record – This record uses ‘Host identity protocol’, a way to separate the roles of an IP address; this record is used most often in mobile computing.
  • 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.
  • NAPTR record – The ‘name authority pointer’ record can be combined with an SRV record to dynamically create URIs to point to based on a regular expression.
  • NSEC record – The ‘next secure record’ is part of DNSSEC, and it’s used to prove that a requested DNS resource record does not exist.
  • RRSIG record – The ‘resource record signature’ is a record to store digital signatures used to authenticate records under DNSSEC.
  • RP record – This is the ‘responsible person’ record, and it stores the email address of the person responsible for the domain.
  • SSHFP record stores the ‘SSH public key fingerprints’; SSH stands for Secure Shell and is a cryptographic networking protocol for secure communication over an unsecured network.