Understanding DNS Records (A, CNAME, MX, TXT)

Introduction

DNS (Domain Name System) records are instructions that tell the internet how to handle requests for your domain. Understanding these records is essential for managing your website, email, and other online services. This guide explains the most common DNS record types and how to manage them.

What is DNS?

DNS is like the internet's phone book. It translates human-readable domain names (like yourdomain.com) into computer-readable IP addresses (like 192.168.1.1). DNS records are the entries in this phone book that specify where different services for your domain are located.

Common DNS Record Types

A Record (Address Record)

Purpose: Points a domain or subdomain to an IPv4 address

Common Uses:

• Pointing your main domain to your web server
• Pointing subdomains to specific servers
• Directing www to your website

Example:

• Name: @ (or blank, represents yourdomain.com)
• Type: A
• Value: 192.0.2.1 (your server IP)
• TTL: 14400

Result: When someone visits yourdomain.com, they're directed to the server at 192.0.2.1

AAAA Record

Purpose: Points a domain or subdomain to an IPv6 address (newer IP format)

Common Uses:

• Same as A record but for IPv6
• Increasingly important as internet moves to IPv6

Example:

• Name: @
• Type: AAAA
• Value: 2001:0db8:85a3:0000:0000:8a2e:0370:7334

CNAME Record (Canonical Name)

Purpose: Points a domain or subdomain to another domain name (alias)

Common Uses:

• Pointing www to your main domain
• Creating subdomains that point to external services
• CDN configuration

Example:

• Name: www
• Type: CNAME
• Value: yourdomain.com

Result: www.yourdomain.com points to wherever yourdomain.com points

Important Rules:

• Cannot create CNAME for root domain (@)
• CNAME cannot coexist with other records for the same name
• CNAME must point to a domain name, not an IP address

MX Record (Mail Exchange)

Purpose: Specifies mail servers responsible for receiving email

Common Uses:

• Directing email to your hosting provider's mail server
• Configuring Google Workspace / Microsoft 365 email
• Setting up custom email solutions

Example:

• Name: @ (or yourdomain.com)
• Type: MX
• Value: mail.yourdomain.com
• Priority: 0 (lower number = higher priority)

Multiple MX Records:

You can have multiple MX records for redundancy:

• Priority 0: mail.yourdomain.com (primary)
• Priority 10: mail2.yourdomain.com (backup)

TXT Record (Text Record)

Purpose: Stores text information for various purposes

Common Uses:

• SPF (Sender Policy Framework) - email authentication
• DKIM (DomainKeys Identified Mail) - email authentication
• DMARC (Domain-based Message Authentication) - email policy
• Domain verification for services (Google, Microsoft, etc.)
• Site verification codes

Example SPF Record:

• Name: @
• Type: TXT
• Value: v=spf1 include:_spf.yourhostingprovider.com ~all

Example Domain Verification:

• Name: @
• Type: TXT
• Value: google-site-verification=abc123xyz789

NS Record (Nameserver)

Purpose: Specifies authoritative nameservers for the domain

Common Uses:

• Delegating subdomains to different nameservers
• Usually managed at registrar level, not in cPanel

Note: Typically, you don't need to edit NS records in cPanel, as these are set at your domain registrar.

SRV Record (Service Record)

Purpose: Specifies location of specific services

Common Uses:

• Microsoft 365 services
• VoIP / SIP services
• Gaming servers
• XMPP/Jabber chat services

Example:

• Service: _sip
• Protocol: _tcp
• Port: 5060
• Target: sip.yourdomain.com
• Priority: 10
• Weight: 60

Managing DNS Records in cPanel

Accessing Zone Editor

1. Log into cPanel
2. Navigate to "Domains" section
3. Click "Zone Editor"
4. Select your domain (or click "Manage" next to it)

Adding a DNS Record

1. In Zone Editor, click "+ Add Record" or the specific record type button
2. Enter record details:
   • Name: Subdomain or @ for root domain
   • TTL: Time to Live (14400 is common)
   • Type: Select record type (A, CNAME, MX, etc.)
   • Record: Destination (IP, domain, or text value)
3. Click "Add Record" to save

Editing a DNS Record

1. Find the record in the list
2. Click "Edit" next to the record
3. Modify the values
4. Click "Save Record"

Deleting a DNS Record

1. Find the record in the list
2. Click "Delete" next to the record
3. Confirm deletion

Warning: Deleting critical DNS records (A, MX) can break your website or email. Always verify before deleting.

Common DNS Configurations

Basic Website Setup

@ (root)     A      192.0.2.1
www          CNAME  yourdomain.com
mail         A      192.0.2.1
@            MX     mail.yourdomain.com (Priority: 0)

Using Google Workspace for Email

@  MX  ASPMX.L.GOOGLE.COM (Priority: 1)
@  MX  ALT1.ASPMX.L.GOOGLE.COM (Priority: 5)
@  MX  ALT2.ASPMX.L.GOOGLE.COM (Priority: 5)
@  MX  ALT3.ASPMX.L.GOOGLE.COM (Priority: 10)
@  MX  ALT4.ASPMX.L.GOOGLE.COM (Priority: 10)

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

Subdomain for Application

app  A  192.0.2.50

Result: app.yourdomain.com points to 192.0.2.50

CDN Configuration

www  CNAME  xyz123.cloudfront.net

TTL (Time To Live) Explained

What is TTL?

TTL specifies how long (in seconds) DNS records should be cached before checking for updates.

Common TTL Values

• 300 (5 minutes): Use when making frequent changes
• 3600 (1 hour): Reasonable for active development
• 14400 (4 hours): Default for most records
• 86400 (24 hours): For stable, rarely-changed records

Best Practices

• Lower TTL (300) before making major DNS changes
• Wait for old TTL to expire before making changes
• Increase TTL (86400) after changes stabilize to reduce DNS queries

Email Authentication Records

SPF (Sender Policy Framework)

Purpose: Specifies which mail servers can send email for your domain

Example:

v=spf1 include:_spf.yourhostingprovider.com ~all

Components:

• v=spf1 - SPF version
• include:_spf.yourhostingprovider.com - Authorized servers
• ~all - Soft fail for unauthorized servers

DKIM (DomainKeys Identified Mail)

Purpose: Adds digital signature to verify email authenticity

DKIM records are usually auto-generated in cPanel. You can find them in:

1. cPanel > Email > Email Deliverability
2. Click "Manage" next to your domain
3. View DKIM record (or install if not present)

DMARC (Domain-based Message Authentication)

Purpose: Specifies policy for handling emails that fail SPF/DKIM

Example:

_dmarc  TXT  v=DMARC1; p=quarantine; rua=mailto:dmarc@yourdomain.com

DNS Propagation

What is Propagation?

When you change DNS records, the changes don't take effect immediately worldwide. Propagation is the time it takes for DNS changes to spread across the internet.

Propagation Time

• Typical: 1-4 hours
• Maximum: Up to 48 hours (rare)
• Affected by: TTL value of old record

Checking Propagation

• WhatsMyDNS.net
• DNSChecker.org
• Command line: nslookup yourdomain.com or dig yourdomain.com

Troubleshooting DNS Issues

Website Not Loading

• Verify A record points to correct IP address
• Check DNS propagation status
• Ensure nameservers are correct
• Clear browser cache and DNS cache

Email Not Working

• Verify MX records point to correct mail server
• Ensure MX record priority is set correctly
• Check SPF record is configured
• Wait for DNS propagation

Subdomain Not Resolving

• Verify A or CNAME record exists for subdomain
• Check for typos in record name or value
• Wait for propagation
• Clear DNS cache

CNAME Conflicts

Error: "CNAME record already exists" or "CNAME conflicts with other records"

• Delete conflicting A or other records first
• Remember: CNAME cannot coexist with other record types for same name
• Use A record instead if CNAME doesn't work

Best Practices

Security

• Enable SPF, DKIM, and DMARC for email authentication
• Regularly audit DNS records for unauthorized changes
• Use strong passwords for cPanel and domain registrar accounts
• Enable two-factor authentication where available

Management

• Document all DNS changes and their purposes
• Lower TTL before making major changes
• Test changes before deploying to production
• Keep records organized and remove unused entries
• Backup DNS zone files periodically

Performance

• Use appropriate TTL values (higher for stable records)
• Minimize number of DNS lookups when possible
• Use CNAME for aliases rather than duplicate A records

Advanced Topics

CAA Records

Control which Certificate Authorities can issue SSL certificates for your domain:

@  CAA  0 issue "letsencrypt.org"

Wildcard DNS

Point all subdomains to the same location:

*  A  192.0.2.1

Result: any.subdomain.yourdomain.com points to 192.0.2.1

Need Help?

DNS can be complex. If you need assistance with DNS configuration, please contact our support team with:

• Your domain name
• What you're trying to achieve
• Any error messages
• Screenshots of current DNS settings (if applicable)