Free online network tools, including traceroute, nslookup, dig, whois, ping, and our own Domain Dossier and Email Dossier. Works with IPv6.
An open source intelligence tool to crawl the graph of certificate Alternate Names
Finds certificates and subdomains using Certificate Transparency data. An alternative to crt.sh that presents the information a bit differently.
DNS History archives historical DNS records, letting investigators track IP changes, hosting migrations, and infrastructure pivots over time.
DNS Twister generates and monitors domain permutations for typosquatting detection, brand protection, and phishing infrastructure discovery.
Free DNS, WHOIS, and email-authentication lookups for any domain: SPF analysis with the 10-lookup limit check, DKIM selector discovery, DMARC checks, email header analysis, and blacklist checks. Results explain in plain English what each record means. No account needed for basic lookups; free API tier available.
DomainTools provides WHOIS lookup, IP history, domain ownership records, and reverse WHOIS for domain and infrastructure investigation.
DNS Tools, Domain lookups and universal Whois utility by easyDNS
Hunting New Registered Domains monitors freshly registered domain names for phishing, typosquatting, and emerging threat infrastructure.
SecurityTrails provides historical DNS records, WHOIS history, subdomain enumeration, and IP intelligence for domain and infrastructure investigation.