DNS records are instructions attached to names within a domain. Understanding their purpose helps a small business approve changes without treating an entire DNS zone as an unexplained block of technical text.
Core website records
| Type | Meaning | Example use |
|---|---|---|
| A | Maps a hostname to an IPv4 address | example.co.uk to a web server |
| AAAA | Maps a hostname to an IPv6 address | IPv6-capable web service |
| CNAME | Makes one hostname an alias of another | www to a hosted platform name |
| NS | Delegates DNS authority | Using a dedicated DNS provider |
Email and verification records
| Type | Meaning | Example use |
|---|---|---|
| MX | Lists receiving mail servers and priorities | Business mailbox provider |
| TXT | Stores text-based policies or tokens | SPF, DMARC and service verification |
| DKIM TXT/CNAME | Publishes a sending service’s public key or pointer | Message authentication |
| CAA | Limits which certificate authorities may issue | Certificate policy control |
Hostnames matter
Providers describe the left-hand field as name, host or label. A value such as @ may mean the zone apex, while _dmarc and selector._domainkey are special subnames. Control panels may automatically append the domain, so copying the full name can accidentally duplicate it.
TTL and caching
Time to live tells resolvers how long an answer may be cached. Lowering a TTL before a planned migration can shorten the caching period, but it must be done early enough for previous values to expire. Very low TTLs are not a substitute for a correct change plan.
Review records as assets
- Record the service owner and purpose.
- Remove a record only after the related service is retired.
- Avoid multiple SPF records at the same hostname.
- Check both IPv4 and IPv6 destinations.
- Treat nameserver and MX changes as high-risk.
Records often confused with one another
An MX record identifies where incoming mail is delivered; it does not authorise outbound senders. SPF is normally published as a TXT record and identifies permitted sending infrastructure. DKIM publishes a public key used to verify a signature. DMARC describes alignment, reporting and the policy for messages that fail authentication.
Likewise, a CNAME is an alias between hostnames, not a general redirect to a web page. Browser redirects are configured by the website, CDN or server after DNS has delivered the visitor to a service.
Final publication check
- Each important record has a known service and owner.
- MX, SPF, DKIM and DMARC are not confused with one another.
- Obsolete IPv4 and IPv6 destinations have been reviewed.
- A CNAME is not being used as a substitute for an HTTP redirect.
Sources and date checked
Technical and policy information was checked on 21 July 2026. Recheck provider-specific procedures before making a live change.
Keep the decision under your control
Retain the relevant accounts, source material, supplier terms and recovery information. Recheck changing prices, interfaces and rules before acting.