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About Network Lookup.

Free network diagnostic and security tools — results in seconds, in plain language.

What we do

Network Lookup is a collection of free tools for network engineers, security professionals, system administrators, and anyone who needs to look up an IP address, check DNS records, or verify email authentication. Everything works instantly.

Every device on the internet has a paper trail: an IP address, an autonomous system, a set of DNS records, a TLS certificate. Most of that information is public. It's just scattered across a dozen different tools, APIs, and registries that were built for engineers, not people. Network Lookup puts it in one place, in plain language, with results in seconds.

The tools

41 tools at the moment, covering:

Many tools run entirely in your browser for maximum privacy. Server-side tools use Cloudflare's global network for fast, low-latency lookups.

Who it's for

  • Developers diagnosing why a DNS change hasn't propagated, or tracing where an outbound request is actually going.
  • Network and security engineers who need a quick sanity check on routing, records, or certificates without opening five terminals.
  • Security analysts correlating IPs from logs with ASN, geolocation, and reputation data.
  • Email administrators debugging SPF / DKIM / DMARC and deliverability.
  • Students and curious people learning how the internet works — what an IP address actually is, why DNS has so many record types, what DNSSEC actually validates.

We also write about these topics in the blog — short, honest explanations without the jargon-without-definition problem that plagues most networking documentation.

How it's built

  • Static site on Cloudflare Pages — fast, served from Cloudflare's global CDN.
  • Server-side tools run on Cloudflare Workers — edge computing, low latency, close to the user.
  • IP geolocation via MaxMind GeoLite2 — loaded from R2 storage and queried in-process; no third-party API calls for geolocation.
  • DNS lookups via Cloudflare DNS-over-HTTPS — RFC 8484 DoH against 1.1.1.1.
  • Open standards throughout — RFC-compliant implementations for SPF (7208), DMARC (7489), DKIM (6376), DNSSEC (4033/4034/4035), CAA (8659), and the rest. Where we depart from a standard, the tool's prose says so.

The principles

Open tools. Ads (via Google AdSense) help cover hosting costs and are clearly labelled.

Honest about data quality. IP geolocation is imprecise. WHOIS data is often redacted. BGP routing can change daily. Where accuracy matters, we say so — and we link to the source so you can verify.

Privacy-respecting analytics. Aggregate traffic comes from Cloudflare Web Analytics (cookieless, no fingerprinting). We don't run Google Analytics, Facebook Pixel, or similar trackers. The one exception is advertising: Google AdSense may set third-party cookies for ad personalisation and frequency capping — you can opt out via the links in our privacy policy.

Who's behind it

Network Lookup is built and maintained by the Network Lookup Team — a small independent team with backgrounds in cybersecurity and networking. The tools and writing here come from years of having to debug exactly these problems for real systems: SPF records that don't validate, DNS that refuses to propagate, certificates issued by a CA you've never used, IP geolocation that swears your office in Madrid is in Frankfurt.

No VC backing, no investor pressure, no corporate owner setting quarterly targets. This is a tool built because the tools we wanted didn't quite exist in the form we wanted them. That means things break sometimes. Data is occasionally wrong. When that happens, we want to know.

Contact

Email: contact@networklookup.com

If a tool is wrong, slow, or confusing, tell us — short bug reports beat polite complaints. The fastest route is the contact page.

See also: privacy policy · terms · data sources