What is a DNS record?
A practical reference guide to DNS records, including what they contain, what common fields mean, and how different record types are used in real DNS setups.
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What a DNS record is
A DNS record is a structured piece of data published in the Domain Name System for a domain or hostname. Different record types answer different questions, such as where a hostname points, which mail system receives email, or which services are authorised to send mail.
In practical terms, DNS records are the instructions that make websites accessible, email deliverable, and many cloud services function correctly.
Common record components
Although formats vary by record type, most DNS records can be understood by breaking them into a few core components.
- Hostname or Name: the label the record applies to
- TTL: time to live, which controls caching duration
- Type: the record type, such as A, MX, TXT, CNAME, or NS
- Value or Data: the actual information the record provides
Understanding these fields makes it much easier to interpret DNS output and troubleshoot issues.
What TTL means
TTL (time to live) defines how long a resolver may cache a DNS response before it must be refreshed.
For example, a TTL of 300 means the result may be cached for roughly five minutes, while a TTL of 3600 means approximately one hour.
TTL directly affects how quickly DNS changes propagate and how long outdated data may persist in caches.
Common record types
- A record: maps a hostname to an IPv4 address
- AAAA record: maps a hostname to an IPv6 address
- CNAME record: aliases one hostname to another hostname
- MX record: defines mail routing targets for a domain
- TXT record: stores text values used for policy or verification
- NS record: identifies authoritative nameservers
- PTR record: maps an IP address back to a hostname
- CAA record: restricts which certificate authorities may issue certificates
Example: reading a basic DNS record
A simple A record might appear as follows:
www.yourdomain.com. 300 IN A 203.0.113.10This means www.yourdomain.com resolves to the IPv4 address 203.0.113.10, and resolvers may cache that result for approximately five minutes.
Why DNS records matter in real life
Incorrect DNS records can prevent users from reaching a website, stop email from being delivered, break service integrations, or cause partial failures during migrations.
Because of this, DNS is often one of the first areas checked when troubleshooting connectivity, email, or application issues.
How records work together
DNS records rarely operate in isolation. Many services rely on multiple record types working together.
For example, email delivery depends on MX records for routing, SPF and DKIM for authentication, and DMARC for policy enforcement.
Common mistakes
- Confusing the hostname with the value
- Editing the wrong record type
- Ignoring TTL when validating changes
- Leaving outdated records in place after migrations
- Not understanding how different record types interact
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