Three Diagnostic Engines. One Unified Console.
Select or hover any engineering domain below to inspect its telemetry core and jump straight into specialized utilities.
Global Routing & DNS Core
Authoritative RIR, ASN, PTR & Zone Diagnostics
Query global Regional Internet Registries, inspect live A/AAAA/MX/TXT/SOA records, resolve CIDR reverse DNS blocks, and model subnet architectures in milliseconds.
Zero-Trust TLS & Threat Shield
Live X.509 Handshakes, DNSBL & HTTP Posture
Validate TLS certificate chains and expiration windows, audit IP reputation across major spam/threat blacklists, inspect CSP/HSTS headers, and verify port exposure.
DevOps & Pipeline Telemetry
Schema Linting, Cron Schedules & Text Pipelines
Format and validate strict JSON/JSONC payloads, verify Docker Compose and CI/CD workflows, generate cryptographic hashes, and process multi-line log streams.
Global Routing & DNS Core
Authoritative RIR, ASN, PTR & Zone Diagnostics
Engineered for Clarity Under Pressure
Network & SRE Teams
Trace ASN ownership, verify global DNS propagation, calculate CIDR subnets, and validate IPv6 routing in seconds.
Security Analysts
Investigate suspicious IPs, inspect X.509 certificate chains, audit HTTP security headers, and check DNSBL feeds.
Email Operations
Diagnose inbox placement by auditing MX, SPF, DKIM, DMARC, and reverse PTR alignment from one clean interface.
Full-Stack Developers
Lint JSON/JSONC, validate Docker Compose & CI/CD configs, minify assets, and share permalink diagnostics in tickets.
Popular Diagnostics & Guides
WHOIS IP Lookup
Look up IP ownership, ASN and RIR allocation details.
DNS Records Lookup
Check A, AAAA, MX, TXT, NS, SOA and more.
Reverse DNS Lookup
Resolve PTR records and hostnames for IPs and CIDRs.
Email Validator
Validate MX, SPF, DKIM and DMARC setup.
SSL Checker
Inspect certificate expiry, issuer and TLS details.
IP Blacklist Checker
Check whether an IP is listed on major DNSBLs.
HTTP Header Analyzer
Audit response headers and common security headers.
Subnet Calculator
Calculate ranges, masks, hosts and broadcast addresses.
Frequently Asked Questions
What is NetworkWhois?
NetworkWhois is a free collection of 32 network diagnostic, security, email, and developer utilities. Run IP WHOIS and reverse DNS lookups, audit TLS certificates, and troubleshoot connectivity without installing anything.
Are these tools really free?
Yes. Core diagnostic tools are completely free to use. A small set of active infrastructure tools require a free account to prevent network abuse.
Do I need an account to use the tools?
27 of our 32 utilities work instantaneously without registration. Advanced active probes (Port Scanner, Speed Test, BGP Lookup, CI/CD Config, and Git Digest) unlock with a free account.
How accurate are the results?
Results are queried directly from authoritative DNS resolvers, Regional Internet Registries (ARIN, RIPE, APNIC, LACNIC, AFRINIC), and live TLS handshakes in real time.
What should I use for email deliverability issues?
Start with Email Validator to inspect MX, SPF, DKIM, and DMARC policies, then verify your sending IP on IP Blacklist Checker and confirm matching PTR records via Reverse DNS.
What’s the difference between WHOIS and reverse DNS?
WHOIS identifies the registered organization, ASN, and allocation block for an IP range. Reverse DNS maps a specific IP to a hostname via PTR records and is critical for mail server trust.