DNS Lookup — A, AAAA, MX, TXT, NS, CNAME, SOA

DNS Lookup

The Domain Name System is the phone book of the internet: it maps human-readable names like example.com to the machine addresses and service records that actually route traffic. This tool queries live, authoritative DNS and shows every common record type at once.

What each record means

• A / AAAA — the IPv4 and IPv6 addresses the name points at. This is what a browser ultimately connects to.
• MX — mail exchangers, in priority order. Where email for the domain is delivered.
• TXT — free-form text records. In practice this is where SPF, DKIM and DMARC policies, domain-verification tokens, and similar metadata live.
• NS — the authoritative name servers for the zone.
• CNAME — an alias pointing one name at another.
• SOA — the "start of authority": the primary name server, the zone contact, and the serial/refresh/retry/expire timers that govern how the zone propagates.

Why it matters for security

DNS is a first-class reconnaissance and defence surface. Missing or misconfigured SPF/DKIM/DMARC TXT records let attackers spoof your email. Stale A records pointing at decommissioned infrastructure are a classic subdomain-takeover vector. An unexpected NS delegation can indicate a hijack. Reading the full record set at a glance is the fastest way to spot these.

Common mistakes

• Assuming a domain has one IP — round-robin DNS and CDNs return many, and they change.
• Forgetting that TXT records are size-limited and often split into multiple strings that must be concatenated.
• Editing a record and testing immediately — resolvers cache by TTL, so propagation lags.