DNS (Domain Name System) records are essential for directing traffic on the internet. They map domain names to IP addresses, specify mail servers, and provide other information about a domain. This article explains common DNS record types including A, AAAA, CNAME, MX, TXT, SRV, and NS, detailing their purposes, formats, and real-world examples.

A Record (IPv4 Address)

The A record maps a domain name to an IPv4 address. This is the most basic DNS record type used for directing traffic to web servers.

  • Purpose: To associate a hostname with an IPv4 address.
  • Format: Domain Name, TTL (Time to Live), Record Type (A), IPv4 Address
  • Example: www.internetport.se. 3600 IN A 192.168.1.1

AAAA Record (IPv6 Address)

The AAAA record is similar to the A record but maps a domain name to an IPv6 address.

  • Purpose: To associate a hostname with an IPv6 address.
  • Format: Domain Name, TTL, Record Type (AAAA), IPv6 Address
  • Example: www.internetport.se. 3600 IN AAAA 2001:db8::1

CNAME Record (Alias)

The CNAME record creates an alias for a domain name, pointing it to another domain.

  • Purpose: To create an alias for a domain name.
  • Format: Alias Domain Name, TTL, Record Type (CNAME), Canonical Name
  • Example: mail.internetport.se. 3600 IN CNAME mailserver.internetport.se.

MX Record (Mail Exchange)

The MX record specifies the mail server responsible for receiving emails sent to a domain.

  • Purpose: To specify the mail server for a domain.
  • Format: Domain Name, TTL, Record Type (MX), Preference Value, Mail Server
  • Example: internetport.se. 3600 IN MX 10 mail.internetport.se.

TXT Record (Text)

The TXT record is used for storing text data associated with a domain, often for SPF, DKIM, or verification purposes.

  • Purpose: To store text information about the domain.
  • Format: Domain Name, TTL, Record Type (TXT), Text Data
  • Example: internetport.se. 3600 IN TXT "v=spf1 include:_spf.google.com ~all"

SRV Record (Service)

The SRV record is used to locate services on a domain, commonly for VoIP and Microsoft Teams.

  • Purpose: To specify the location of services such as VoIP or Teams.
  • Format: Service Name, Protocol, Domain Name, TTL, Record Type (SRV), Priority, Weight, Port, Target
  • Example: _sip._tcp.internetport.se. 3600 IN SRV 10 50 5060 sipserver.internetport.se.

NS Record (Name Server)

The NS record specifies the authoritative DNS servers for a domain, delegating control over DNS records.

  • Purpose: To specify the authoritative DNS servers for a domain.
  • Format: Domain Name, TTL, Record Type (NS), Authoritative DNS Server
  • Example: internetport.se. 3600 IN NS ns1.internetport.se.

Troubleshooting Tips

If you encounter issues with DNS records, consider the following troubleshooting steps:

  1. Verify that all DNS records are correctly formatted and entered into your DNS management console.
  2. Ensure that TTL (Time to Live) values are appropriate for your needs; lower TTLs allow changes to propagate faster but can increase server load.
  3. Use online tools like dig, nslookup, or What's My DNS to check the status of your DNS records across different DNS servers.
  4. If you recently made changes, allow time for them to propagate; this can take up to 48 hours depending on TTL settings.
  5. Contact Internetport support if you continue to experience issues after verifying and troubleshooting your DNS records.