DNS Lookup

Query A, AAAA, MX, NS, TXT, CNAME, SOA, and PTR records for any domain

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Frequently Asked Questions

DNS (Domain Name System) is the internet's phonebook — it translates human-readable domain names like example.com into machine-readable IP addresses. A DNS lookup queries DNS servers to retrieve these records. Different record types store different information: A records store IPv4 addresses, MX records store mail server info, TXT records store text (often used for domain verification), etc.

An A record (Address record) maps a domain name to an IPv4 address (e.g., 93.184.216.34). It is the most fundamental DNS record type — when a browser looks up a website, it typically queries the A record first. A domain can have multiple A records for load balancing.

An MX (Mail Exchanger) record specifies the mail servers responsible for accepting email for a domain. MX records include a priority value — lower numbers = higher priority. A domain can have multiple MX records for redundancy (e.g., Google Workspace uses aspmx.l.google.com with priority 1).

TXT records store arbitrary text data associated with a domain. Common uses include: SPF (Sender Policy Framework) records for email anti-spoofing, DKIM public keys for email signing, DMARC policies, and domain verification tokens for Google Search Console, GitHub Pages, and similar services.

A CNAME (Canonical Name) record creates an alias from one domain to another. For example, www.example.com might CNAME to example.com. When a DNS resolver sees a CNAME, it continues the lookup to resolve the target. Note: you cannot have a CNAME at a zone apex (root domain).

TTL (Time To Live) is the number of seconds a DNS record is cached by resolvers before they query the authoritative server again. A TTL of 3600 means the record is cached for 1 hour. Lower TTLs allow faster propagation of DNS changes but increase server load. Common TTL values are 300 (5 min), 3600 (1 hr), and 86400 (1 day).

DNS propagation is the time it takes for DNS changes (such as updating an A record or changing nameservers) to spread across all DNS resolvers worldwide. It can take anywhere from a few minutes to up to 48 hours, depending on the TTL (Time To Live) of the old record. If the previous record had a TTL of 86400 (24 hours), resolvers that cached it will keep using the old value for up to 24 hours. To speed up propagation, lower your TTL to 300 seconds (5 minutes) before making the change. After propagation completes, you can raise the TTL again.

A record — Maps a domain name directly to an IPv4 address (e.g. example.com → 93.184.216.34). The most fundamental DNS record type.

AAAA record — Maps a domain name to an IPv6 address (e.g. example.com → 2606:2800:220:1:248:1893:25c8:1946). The IPv6 equivalent of the A record.

CNAME record — Creates an alias from one name to another (e.g. www.example.com → example.com). The resolver follows the CNAME chain to the final A/AAAA record. CNAMEs cannot be used at the zone apex (root domain) and cannot coexist with other record types at the same name.

A DNS resolver (recursive resolver) is what your computer or ISP queries. It does not hold DNS records itself — instead, it queries other DNS servers on your behalf, caches the results, and returns the answer. Common resolvers include 8.8.8.8 (Google), 1.1.1.1 (Cloudflare), and your ISP's default.

An authoritative nameserver is the server that holds the actual DNS records for a domain. When a resolver needs to look up example.com, it ultimately queries the authoritative nameserver for that domain (found via the domain's NS records) to get the definitive answer.

Flushing your DNS cache forces your computer to query DNS servers fresh instead of using cached (possibly stale) records. Commands by operating system:

Windows: ipconfig /flushdns in Command Prompt (run as Administrator)
macOS (Sonoma/Ventura): sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
Linux (systemd-resolved): sudo systemd-resolve --flush-caches
Chrome browser: navigate to chrome://net-internals/#dns and click "Clear host cache"

This is useful after DNS changes when your local cache is serving the old IP.

About This DNS Lookup Tool

This free DNS Lookup tool queries the DNS system in real time for any domain. It supports all major record types including A, AAAA, MX, NS, TXT, CNAME, SOA, and PTR. Results include the value, TTL, and any record-specific fields like MX priority or SOA serial number.

DNS Record Types

Type	Purpose
A	Maps domain to IPv4 address
AAAA	Maps domain to IPv6 address
MX	Mail exchange servers
NS	Nameservers for the domain
TXT	Text data (SPF, DKIM, etc.)
CNAME	Alias to another domain
SOA	Start of Authority record
PTR	Reverse DNS pointer

Common TTL Values

TTL	Duration	Use Case
60	1 minute	During migrations
300	5 minutes	Dynamic/changing
3600	1 hour	Standard
86400	24 hours	Stable records
604800	1 week	Rarely changed

Standards & References

In-depth guides and technical articles.

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Internet Jul 3, 2026

DNSSEC Protects Against Cache Poisoning — Not the Attacks That Actually Cause DNS Outages

DNSSEC signs DNS records cryptographically — protecting against cache poisoning (Kaminsky's 2008 attack) but doing nothing about registrar account compromise, BGP hijacking, or misconfigured records. Here's how DNSSEC's chain of trust works (root → TLD → domain), why expired RRSIG signatures cause SERVFAIL for DNSSEC-validating resolvers including Google and Cloudflare, and why only ~3-5% of .com domains have DNSSEC despite most TLDs being signed.

Internet Jun 23, 2026

The Four-Layer DNS Cache — Why the Same Domain Resolves Differently From Different Locations During Propagation

A DNS query might return an answer cached by your browser, your OS, your ISP's resolver, or a CDN's resolver — and each cache has a different expiry time. Here's the four-layer DNS caching chain, why the TTL on your old record controls propagation speed (not the TTL on the new one), how to read the remaining cache TTL from dig output, negative caching (why "doesn't exist" responses are also cached), and why Anycast DNS means propagation isn't geographically simultaneous.

Internet Jun 16, 2026

DNS Propagation, TTLs, and Caching: What Actually Happens When You Change a DNS Record

"DNS propagation takes up to 48 hours" is true but vague — the actual mechanism is TTL-governed caching at thousands of independent resolvers, each expiring on its own schedule. Here's how TTL actually controls this, why lowering TTL before a planned change matters, negative caching for new records, and why different users can genuinely see different DNS results during a transition.

Internet Jun 15, 2026

DNS over HTTPS: Why Your Browser and Your DNS Lookup Tool Might Be Talking to Different Servers

Your computer's DNS settings and your browser's actual DNS resolution might be using completely different servers — DNS over HTTPS (DoH), increasingly implemented at the browser level, can bypass OS-level DNS settings entirely. Here's why DoH/DoT exist (encrypting DNS queries for privacy), why "dig shows the new record but my browser doesn't" can happen due to separate resolver caches, and how DoH interacts with network-level DNS filtering.

Internet Jun 9, 2026

DNS as a Security Tool and Target: Cache Poisoning, Hijacking, and DNSSEC

DNS cache poisoning, DNS hijacking, and DNS tunneling are real attack vectors. Here's how each works, what DNSSEC does (and doesn't) protect against, how to monitor your own DNS records for unexpected changes, and what domain shadowing is.