DNS records are the instructions that tell the internet how to route traffic and email for your domain. Missing or incorrect records are a common, easy-to-overlook cause of both downtime and email delivery problems.
The essentials
- A record: points a domain to an IPv4 address (your server)
- AAAA record: the IPv6 equivalent of an A record
- CNAME record: points a subdomain to another domain name (commonly used for
wwwor third-party services) - MX record: routes email for the domain to the correct mail server
- TXT record: holds text-based verification and policy data — this is where SPF, DKIM, and DMARC records live
- NS record: declares which nameservers are authoritative for the domain
Why monitoring DNS matters
DNS records can be changed accidentally (a registrar UI mistake) or maliciously (domain/DNS hijacking) without your web server itself ever changing — so DNS-specific monitoring catches a class of incident that uptime checks on the server alone will miss.
FAQ
How long do DNS changes take to go live?
This depends on the record’s TTL (time-to-live) setting, and can also be delayed further by DNS caching at ISPs; changes are rarely instant everywhere.