Network Diagnostics Simplified
NetLookup is a focused suite of 12 free network diagnostic tools — DNS lookup, IP geolocation, SSL certificate checks, HTTP & security header inspection, ping, traceroute, port checks, WHOIS, and blacklist lookups. Browser UI and JSON API, no signup.
12
Free Tools
3
Tool Categories
22
RBL Databases
99.9%
Uptime
Everything You Need to Diagnose, Debug & Verify
12 essential tools organised into 3 focused categories — each runs against authoritative sources and returns structured, human-readable results.
Network Tools
Identify your IP, geolocate any address, ping a host, trace a route, check open ports, and calculate subnets.
- What Is My IP
- IP Address Lookup
- Ping
- Traceroute
- Port Checker
- Subnet Calculator
DNS & Domain Tools
Query any DNS record type, watch propagation across 10+ global DoH resolvers, and pull WHOIS registrar data.
- DNS Lookup
- DNS Propagation Checker
- WHOIS Lookup
Web & Security Tools
Inspect TLS certificates, grade HTTP & security headers, and check IPs against 22 major DNSBL blacklists.
- SSL Certificate Checker
- HTTP & Security Headers
- Blacklist (RBL) Lookup
Built for Speed
Beyond the individual tools, NetLookup ships a few features that make day-to-day diagnostics feel effortless.
Smart Input
One universal field — paste a domain, IP, or URL and NetLookup detects what you meant and routes to the right tool.
What Is My IP — Auto-Run
Resolves your public IP, country, ISP, OS, and browser on page load — no click required.
Domain Audit
Run DNS, WHOIS, SSL, HTTP headers, and RBL checks in parallel and get back a single graded summary for the domain.
JSON API
Every server-side tool is exposed as POST /api/run/<tool-slug>, returning structured data and a rendered HTML fragment.
Why Teams Choose NetLookup
Professional-grade network diagnostics that stay out of your way — no signup, no ads cluttering results, no paywalls in front of the basics.
100% Free
Every tool is free with no hidden costs. No credit card, no trial period, no feature gating.
Instant Access
No signup, no login. Open a tool and run your query — results in seconds.
Privacy Focused
Queries aren't tied to an account. We don't track what you look up or sell data to third parties.
99.9% Uptime
Redundant infrastructure so the tools are there when you need them — including during your 2am incident.
10+ Global Resolvers
DNS propagation checks query 10+ public DoH resolvers across regions — Google, Cloudflare, Quad9, OpenDNS, NextDNS — so you see what the rest of the world is actually seeing.
Readable Results
Output formatted for humans first — so you can diagnose quickly instead of parsing wall-of-text responses.
Who Uses NetLookup?
Built for the people who keep the internet running — from solo developers debugging a deploy to platform teams chasing a regional DNS issue.
Developers
Debug API endpoints, check CORS, follow redirects, and verify DNS during deploys.
- HTTP header inspection
- CORS & redirect testing
System Admins
Monitor DNS propagation, check mail server health, and confirm port reachability across regions.
- DNS propagation
- Port & SMTP checks
Security Teams
Inspect TLS certificates, grade security headers, and check IPs against 22 major DNSBL blacklists in seconds.
- RBL / DNSBL lookup
- Security header grading
DevOps / SRE
Quick triage during incidents — trace routes, hit 10+ DoH resolvers, and verify TLS without shelling in.
- Traceroute & ping
- SSL certificate inspection
Frequently Asked Questions
Everything you need to know about NetLookup.
Ready to run your first lookup?
12 focused network tools, no signup, no limits on the basics. Bookmark NetLookup and make it your go-to console.