DNS Lookup - Query A, MX, TXT, NS, SOA Records

What is a DNS Lookup?

A DNS lookup queries DNS servers to retrieve live record data for a domain. It helps you verify web routing, mail routing, and authority at the same time.

For migrations and incident response, DNS lookup is the fastest first check because it tells you whether values are actually published before you assume propagation is broken.

💡DNS lookup answers: “What does this resolver return now?” If answers are mixed by region, pair this with a DNS propagation check.

Common DNS Record Types

Record	What it controls	Typical use case
A / AAAA	Maps hostnames to IPv4/IPv6 addresses.	Website or app server cutovers.
CNAME	Aliases one hostname to another.	CDN aliases, SaaS verification hostnames.
MX	Defines inbound mail servers + priorities.	Email routing and failover.
TXT	Stores policy/verification text values.	SPF, DMARC, DKIM selectors, domain verification.
NS / SOA	Authority + zone metadata.	Provider migration and zone diagnostics.

Authoritative vs Recursive Answers

Authoritative nameservers hold the source zone data. Recursive resolvers (Google, Cloudflare, ISP DNS) cache answers for users. If you see mismatch, check both layers before acting.

Layer 1

Authoritative DNS

Best signal for whether the record is configured correctly at the source.

Layer 2

Recursive Resolver

Best signal for what real users currently experience from cached DNS.

When to Use DNS Lookup

Before cutovers: validate record values before switching traffic.
After updates: confirm live record values and TTL behavior.
Email debugging: verify MX and TXT records for authentication flow.
Outage triage: quickly detect wrong/missing records.

Practical Troubleshooting Workflow

Step 1: Query the target record in this DNS lookup tool.
Step 2: Verify NS authority using NS Lookup.
Step 3: Compare regions with DNS Propagation Checker.
Step 4: For mail issues, validate SPF/DMARC/DKIM from Email Tools.

How to Verify in CLI (dig)

# Query A record via Google resolver

dig @8.8.8.8 example.com A

# Query nameserver authority

dig example.com NS +short

# Query MX records

dig example.com MX +short

# Query TXT records

dig example.com TXT +short

Use authoritative NS queries when resolver results conflict. Correct authority + mixed public results usually means normal cache expiry behavior.

Frequently Asked Questions

What is a DNS lookup?

A DNS lookup is a query for DNS records (like A, AAAA, CNAME, MX, TXT, NS, or SOA) to learn how a domain is configured and where it should route traffic.

Why do DNS lookup results differ between tools?

Different tools may query different resolvers (Google, Cloudflare, ISP resolvers) and caches. TTL and DNS caching can cause temporary differences even when the authoritative zone is correct.

What is DNS-over-HTTPS (DoH)?

DNS-over-HTTPS sends DNS queries over HTTPS to a resolver. It helps prevent network interception and often works reliably from browsers and locked-down networks.

What record types should I check for email?

For email deliverability and anti-spoofing, check MX for inbound mail routing, and TXT records for SPF and DMARC. DKIM is usually a selector-based TXT record.

Can I use DNS lookup to troubleshoot propagation?

DNS lookup shows current answers from a resolver, but propagation issues are best diagnosed by comparing multiple regions/resolvers and verifying the authoritative nameserver responses.