What is a DNS lookup?

A DNS lookup is the process of asking a DNS resolver for the records associated with a domain name. The most common record type is A (the IPv4 address the domain points to), but DNS holds dozens of record types: MX for mail servers, TXT for SPF and DKIM, CAA for certificate policy, and so on. Every time you visit a website, your computer runs a DNS lookup to find which server to connect to.

What's the difference between nslookup and dig?

`dig` is the modern replacement. It was written for BIND in the late 1990s and has been the recommended tool since around 2001. It returns more detail by default, handles edge cases like CNAME chains correctly, and is consistent across Linux and macOS. `nslookup` predates dig and ships with Windows; it works for simple lookups but its output format varies between platforms and it has known bugs around CNAME resolution. If you have a choice, use dig. If you're on Windows without WSL, nslookup or PowerShell's `Resolve-DnsName` are your built-in options.

How do I find which DNS server my computer is using?

On Windows, run `ipconfig /all` and look for the DNS Servers line. On macOS, `scutil --dns` shows every configured resolver. On Linux, check `/etc/resolv.conf` (older distros) or `resolvectl status` (newer systemd-based distros). Most home networks default to the ISP's resolver unless you've manually set Google 8.8.8.8, Cloudflare 1.1.1.1, or similar.

How long does DNS propagation take?

It depends entirely on the TTL on the record you changed. If the old record had a 300-second TTL, propagation finishes in 5 minutes. If it had an 86,400-second TTL, propagation takes up to 24 hours. The TTL is published with the old record, so by the time you change it, everyone who already cached the old value will keep serving it until their cache expires. A common pre-migration tactic is to drop the TTL to 60 seconds 24 hours before the cutover.

What is a reverse DNS lookup?

Reverse DNS asks the opposite question: given an IP address, what hostname claims it? Reverse lookups query PTR records in the in-addr.arpa (IPv4) or ip6.arpa (IPv6) zone. They're often used for spam filtering. Mail servers may reject a sender whose IP has no matching PTR or whose PTR doesn't match the HELO hostname. Reverse DNS requires the IP block owner to set the PTR, which usually means your hosting provider or a cloud console.

Can I look up DNS records without the command line?

Yes. That's what this tool does. The lookup card at the top of the page lets you check any record type against five public resolvers in parallel. No installation, no firewall rules, no terminal. For people who DO want the terminal command, we render the equivalent dig, nslookup, and PowerShell commands beneath the result so you can copy them into a ticket or script.

Why do different DNS resolvers return different results?

Three main reasons. First, **caching**: each resolver fetched the record at a different time, so if you've published a change, some have the new value and some still have the old. Second, **policy**: Quad9 blocks malicious domains and OpenDNS supports content filtering on premium plans, so they'll return NXDOMAIN for some names the others answer. Third, **split-horizon**: if you're querying a name that resolves differently inside a corporate VPN versus the public internet, the resolver that goes through the VPN will return different data.

What is DNSSEC and do I need it?

DNSSEC signs DNS responses with cryptographic keys so resolvers can verify the data wasn't forged en route. If you run a domain that matters (banking, government, anything with auth flows), enabling DNSSEC raises the bar against DNS cache poisoning. It does cost some operational overhead (key rollovers have to be sequenced correctly or you can lock yourself out), and DNSSEC adoption is uneven (about 4-5% of zones are signed), so most attackers don't attempt DNS-level forgery anyway. For most small sites the answer is "nice to have, not urgent." For high-stakes domains it should be table stakes.

How accurate are these results?

We query the public DoH endpoints of Google, Cloudflare, Quad9, OpenDNS, and NextDNS directly from your browser. The records you see are the same records those resolvers return to anyone else asking from your network at this moment. The one caveat is caching. Every resolver caches answers for the record's TTL, so if you published a change very recently you may see the old value briefly. Refreshing after the TTL expires gives you the new one.

Is this DNS lookup tool free?

Yes. No signup, no rate limit, no paywall. The lookup runs entirely in your browser using public DoH endpoints. We don't proxy through our servers, log queries, or count them against any quota. Bookmark the URL with `?domain=` and `?type=` in the query string to share a specific lookup with a coworker.

Free DNS Lookup — Check All DNS Records for Any Domain

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