Master the web's
infrastructure.
How DNS, email, SSL, and web infrastructure actually work — explained clearly.
✦ AI-powered — understands natural language
Closed and Filtered Aren't the Same Finding
Reverse DNS Lookup — Translate Any IP Address to Its Hostname
Learn how reverse DNS works, what PTR records reveal about IP addresses, why forward-confirmed reverse DNS matters for email, and how to use a free reverse DNS lookup for security and diagnostics.
Subnet Calculator — IPv4 & IPv6 Network Address, Host Range & CIDR
Learn how IPv4 subnetting works, what CIDR notation means, how to calculate network addresses, host ranges, and usable hosts, with real examples — plus an IPv6 intro and a free subnet calculator.
DMARC Lookup — Check Your Domain's Email Policy & Anti-Spoofing Protection
Learn how DMARC works, what the none/quarantine/reject policies mean, how to read a DMARC record, and how to use a free DMARC lookup to diagnose email authentication and spoofing protection.
SSL Checker — Verify Certificate Validity, Expiry & Chain Instantly
Learn how SSL certificates work, what DV/OV/EV and wildcard certificates mean, how to read SSL checker results, and how to catch certificate expiry before users see browser security warnings.
BIMI Lookup — Check Your Domain's Email Brand Logo Configuration
Learn what BIMI is, how it works alongside DMARC and DKIM to display brand logos in email inboxes, what a BIMI lookup reveals, and how to implement it for your domain.
Blacklist Checker — Is Your IP or Domain on a Spam Blacklist?
Learn how email spam blacklists work, why you might get listed, how to check if your IP or domain is on a blacklist, and how to get removed from the major DNSBLs.
Traceroute Tool — Map the Network Path to Any Host & Find Latency
Learn how traceroute works, how to read hop-by-hop latency results, what * * * means, how to identify congested hops, and how to use a free online traceroute tool for network diagnostics.
WHOIS Lookup — Check Domain Registration, Ownership & Expiry Instantly
Learn what WHOIS reveals about domain ownership, registration dates, expiry, nameservers, and domain status codes — with real examples for security research, competitive analysis, and domain recovery.
