Master the web's
infrastructure.
How DNS, email, SSL, and web infrastructure actually work — explained clearly.
✦ AI-powered — understands natural language
Why 1.1.1.1 Reaches Different Servers Worldwide — Anycast, DNS Propagation, and the 13 Root Nameservers That Are Really 1,500
DNS Lookup — Query Any Record Type for Any Domain Instantly
Learn how DNS works, what record types mean (A, MX, TXT, CNAME, NS), how to diagnose common DNS problems, and how to use a free DNS lookup tool to check any domain's records.
MX Lookup — Check Any Domain's Mail Server Records Instantly
Learn how MX records work, what mail server priorities mean, how to read common configurations for Google Workspace and Microsoft 365, and how to use a free MX lookup tool to diagnose email routing.
Port Scanner — Check Open Ports & Verify Server Security Configuration
Learn how port scanning works, what common port numbers mean, how to identify dangerous open ports, and how to use a free port scanner to verify your server's security posture.
DKIM Checker — Verify Your Domain's Email Signing Key in DNS
Learn how DKIM works, what a DKIM DNS record contains, how to find your selector, and how to use a free DKIM checker to verify your email signing key is correctly published.
Ping Tool — Check Host Reachability & Measure Network Response Time
Learn how ping works, how to read RTT and packet loss results, when a ping timeout doesn't mean a server is down, and how to use a free online ping tool for network diagnostics.
SPF Lookup — Check Any Domain's Email Authentication Record
Learn how SPF records work, what the include, ip4, and all mechanisms mean, why the 10-lookup limit matters, and how to use a free SPF lookup tool to diagnose email authentication failures.
NS Lookup — Find the Authoritative Nameservers for Any Domain
Learn what NS records are, how DNS delegation works, why NS records are the first thing to check when DNS fails, and how to use a free NS lookup tool to verify nameserver configuration.
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.
