Network engineer toolkit — 29 free tools
DNS lookup, WHOIS, port checks, SSL/TLS inspection, CIDR and subnet math, SPF/DMARC parsers, and more. Every tool runs in your browser or on our servers — no signup, no install, no log of your queries.
29 tools liveSee what's planned →
Tip: press ⌘K (or Ctrl-K) to search.
DNS & Domain4
See DNS only →DNS Lookup
Look up DNS records (A, AAAA, MX, TXT, NS, SOA, CAA, SRV, CNAME) for any domain.
DNS Propagation Checker
Compare DNS answers across multiple public resolvers worldwide.
Reverse DNS (PTR) Lookup
Find the hostname assigned to an IP address, with forward-confirm verification.
Domain WHOIS Lookup
Look up registration details for a domain — registrar, dates, nameservers, status.
IP & Routing8
See IP only →What's My IP
Show the public IPv4 or IPv6 address you are connecting from, with geolocation and ASN.
IP Lookup & Geolocation
Get geolocation, ISP, and ASN ownership for any IP address.
IP WHOIS Lookup
Find the network owner, ASN, and registry record for any IP.
ASN Lookup
Look up the AS number behind an IP, or details for any ASN.
CIDR Calculator
Calculate network, broadcast, range, and host count for an IPv4 CIDR.
Subnet Calculator
Split a CIDR block into smaller subnets at any prefix length.
IP Address Converter
Convert IPv4 addresses to/from decimal, hex, and binary.
IP Address Classifier — Public, Private, Reserved
Tell whether an IP is public, private (RFC 1918), loopback, link-local, or reserved.
Connectivity & Diagnostics4
See Connectivity only →TCP Port Check
Check if a TCP port is open, with banner-grab when the service speaks first.
HTTP Headers Inspector
Fetch a URL and inspect response headers, status, and redirect chain.
Redirect Checker
Follow every HTTP redirect and show each hop.
SSL/TLS Certificate Checker
Inspect a server's TLS certificate — expiry, issuer, SANs, chain, protocol.
Email & Security6
See Email only →Email DNS Health Check
One-shot scan of MX, SPF, DMARC, MTA-STS, and TLS-RPT for a domain.
SPF Lookup & Parser
Find and parse the SPF record for a domain.
DMARC Lookup & Parser
Fetch and parse the DMARC policy for a domain.
DKIM Record Lookup
Find DKIM records by trying common selectors, or check a specific one.
MX Record Lookup
Resolve MX, forward-resolve each, check PTR, and probe SMTP ports.
IP Blacklist (RBL/DNSBL) Check
Check an IPv4 against major mail blacklists (Spamhaus, SpamCop, Barracuda, etc.).
Utilities7
See Utilities only →URL Parser
Break a URL into protocol, host, port, path, query, and fragment.
URL Encoder / Decoder
Percent-encode or decode any string for safe use in URLs.
Base64 Encoder / Decoder
Encode or decode UTF-8 text to and from base64.
Hash Generator
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes for any text.
MAC Address Formatter
Convert MAC addresses between colon, hyphen, and Cisco formats; flag locally-administered / multicast.
Random Password & API Key Generator
Generate cryptographically random passwords and API keys.
Regex Tester
Test a regular expression against sample text — see every match, position, and capture group.