DNS records are the mapping layer between domain names and the actual services that power them — your website, your email, your SPF policy, your CDN. When something breaks — email stops delivering, a domain doesn't resolve, SSL validation fails — the answer is almost always in the DNS records.
A DNS lookup tool lets you see those records directly, without command-line tools, without digging into your DNS provider's admin panel, and without waiting for propagation guesswork. This post explains what each record type tells you and when you'd actually want to look it up.
The A record is the most fundamental DNS record. It answers the question: "What IP address does this domain point to?" When a browser navigates to example.com, it resolves the A record to get an IP, then connects to that IP over port 80 or 443.
When to look it up:
Same as the A record but for IPv6. Most modern stacks configure both A and AAAA. If you're seeing connectivity issues from IPv6-native networks, check whether your AAAA record points to a reachable server. A common misconfiguration is having an AAAA record pointing to an address that no longer exists after a server migration — IPv6 users get a connection refused while IPv4 users work fine.
The MX (Mail Exchange) record specifies which server receives email for your domain. It contains a priority (lower = higher priority) and a hostname. A missing or misconfigured MX record means email to your domain bounces or is silently dropped.
When to look it up:
TXT records are used for a wide range of purposes, but the most important in practice are email authentication policies and domain verification tokens:
TXT records are frequently the culprit when email deliverability drops suddenly — an SPF record got deleted, a DKIM selector wasn't configured after switching email providers, or a DMARC policy was set to p=reject prematurely.
A CNAME (Canonical Name) record maps one hostname to another. Instead of pointing www.example.com directly to an IP, you point it to example.com (or to a CDN hostname like xyz.cloudfront.net). The resolver then looks up that target hostname to get the actual IP.
When to look it up:
example.com itself) according to DNS standards. Some DNS providers offer "CNAME flattening" or "ALIAS records" that work around this. If you need to point your root domain to a CDN or load balancer, look for these options in your DNS provider's settings.
NS (Name Server) records identify the authoritative nameservers for your domain. These are the servers that hold the actual DNS records. If your NS records are wrong, your entire domain stops resolving for everyone — nothing works.
NS records are typically set at your domain registrar (not your DNS provider), and they change when you switch DNS providers. When migrating DNS, always verify that your registrar is pointing to the new nameservers before making any other changes.
The fastest way is a browser-based tool that queries DNS-over-HTTPS. No installation, no command-line knowledge required, works from any device:
dig is available by default on Linux and macOS, and installable on Windows via WSL or BIND tools:
# Look up all common record types
dig example.com A
dig example.com AAAA
dig example.com MX
dig example.com TXT
dig example.com CNAME
dig example.com NS
# Short output (answer only)
dig example.com MX +short
# Query a specific resolver
dig @1.1.1.1 example.com Anslookup -type=MX example.com
nslookup -type=TXT example.com
nslookup -type=NS example.comIf you find a record that's wrong, the fix is straightforward: update it in your DNS provider's dashboard. The time it takes to propagate depends on the TTL set on the record — see how DNS propagation works for details on timing.
If you can't find a record that should be there, check whether it was accidentally deleted (most DNS providers keep a change log), and whether you're looking at the right zone (some providers have separate zones for subdomains).
If you find a record that looks wrong but you didn't change it — treat it as an incident. Unauthorized DNS changes are a real attack vector. Lock down DNS provider access and audit who made the change.
A one-time lookup tells you what your DNS looks like right now. But DNS records change — sometimes intentionally (deployments, migrations), sometimes accidentally (provider errors, unauthorized changes). The only way to catch unintended changes before users do is continuous monitoring.
DNSWatch checks your A, AAAA, MX, TXT, CNAME, and NS records continuously and sends an instant alert whenever a value changes. Catch unauthorized changes, misconfigured deployments, and provider incidents before they become user-facing outages.
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