Common DNS Record Types Explained

Understanding DNS Records

DNS records are instructions stored on authoritative nameservers that tell the DNS system how to handle requests for a domain. Each record type serves a specific purpose.

Essential DNS Record Types

A Record (Address Record)

Maps a domain name to an IPv4 address.

• Most fundamental DNS record type
• Points domain directly to a server IP
• Multiple A records enable round-robin load balancing

AAAA Record (IPv6 Address Record)

Maps a domain name to an IPv6 address.

• Identical function to A record but for IPv6
• Increasingly important as IPv6 adoption grows

CNAME Record (Canonical Name)

Creates an alias that points one domain to another domain.

• Cannot coexist with other record types for the same name
• Cannot be used at the zone apex (root domain)
• Commonly used for www subdomains and CDN configurations

MX Record (Mail Exchange)

Specifies the mail servers responsible for receiving email for the domain.

• Priority value determines which server to try first (lower = higher priority)
• Multiple MX records provide mail server redundancy
• Must point to an A or AAAA record, not a CNAME

TXT Record (Text Record)

Stores arbitrary text data, commonly used for verification and security.

• SPF: Specifies authorized mail servers (e.g., "v=spf1 include:_spf.google.com ~all")
• DKIM: Email authentication via digital signatures
• DMARC: Email authentication policy
• Domain Verification: Prove domain ownership to third-party services

NS Record (Nameserver)

Delegates a domain to specific authoritative nameservers.

• Usually set at the registrar level
• Minimum of 2 nameservers recommended for redundancy

SOA Record (Start of Authority)

Contains administrative information about the DNS zone.

• Primary nameserver for the zone
• Email address of the zone administrator
• Serial number, refresh, retry, expire, and minimum TTL values

PTR Record (Pointer Record)

Maps an IP address to a domain name (reverse DNS lookup).

• Opposite of an A record
• Important for email deliverability
• Used in reverse DNS zones

SRV Record (Service Record)

Specifies the location of specific services (host and port).

• Used by VoIP, XMPP, and other protocols
• Includes priority, weight, port, and target

CAA Record (Certificate Authority Authorization)

Specifies which Certificate Authorities may issue certificates for the domain.

• Prevents unauthorized certificate issuance
• CAs are required to check CAA records before issuing