DNS Records Explained: A, CNAME, MX, TXT and More

DNS Records Overview

DNS (Domain Name System) translates domain names to IP addresses. Different record types serve different purposes.

Record Types

A Record (Address)

Points a domain to an IPv4 address:

yourdomain.com    A    192.168.1.100
www.yourdomain.com A   192.168.1.100

Use: Primary domain-to-server mapping.

AAAA Record

Points a domain to an IPv6 address:

yourdomain.com    AAAA    2001:db8::1

Use: IPv6 connectivity (increasingly important).

CNAME Record (Canonical Name)

Creates an alias for another domain:

www.yourdomain.com    CNAME    yourdomain.com
blog.yourdomain.com   CNAME    myapp.vercel.app

Use: Subdomains, CDN integration, platform aliases.

MX Record (Mail Exchange)

Directs email to your mail server:

yourdomain.com    MX    10    mail.yourdomain.com
yourdomain.com    MX    20    backup-mail.yourdomain.com

Priority: Lower numbers = higher priority. Use multiple MX records for redundancy.

TXT Record

Stores text data for various purposes:

SPF (email authentication):

yourdomain.com TXT "v=spf1 include:_spf.google.com ~all"

DKIM (email signing):

selector._domainkey.yourdomain.com TXT "v=DKIM1; k=rsa; p=..."

DMARC (email policy):

_dmarc.yourdomain.com TXT "v=DMARC1; p=quarantine; rua=mailto:[email protected]"

Domain verification:

yourdomain.com TXT "google-site-verification=abc123"

NS Record (Name Server)

Delegates DNS for your domain:

yourdomain.com    NS    ns1.hosting.com
yourdomain.com    NS    ns2.hosting.com

SRV Record (Service)

Specifies server for specific services:

_sip._tcp.yourdomain.com SRV 10 60 5060 sip.yourdomain.com

CAA Record

Controls which CAs can issue SSL certificates:

yourdomain.com    CAA    0 issue "letsencrypt.org"

DNS Propagation

After changing DNS records:

• A/AAAA/CNAME: 1-48 hours (usually under 4 hours)
• MX records: 1-24 hours
• Nameserver changes: 24-48 hours

Speed Up Propagation

• Lower the TTL (Time to Live) before making changes
• Wait for old TTL to expire
• Use dig or online tools to verify propagation

Common Configurations

Website + Email

@       A       203.0.113.10          # Website
www     CNAME   @                     # www alias
@       MX  10  mail.yourdomain.com   # Email
@       TXT     "v=spf1 ..."         # Email auth

Website + Google Workspace Email

@       A       203.0.113.10
@       MX  1   aspmx.l.google.com
@       MX  5   alt1.aspmx.l.google.com
@       TXT     "v=spf1 include:_spf.google.com ~all"

Conclusion

Understanding DNS records gives you control over how your domain works. Most issues with websites and email can be traced back to DNS configuration. Keep this guide handy as a reference.