DNS
Tools that investigate DNS records, subdomains and domain infrastructure.
Amass
In-depth attack-surface mapping and asset discovery via DNS enumeration and network recon.
Open source
DNSDumpster
Free domain research tool that maps a domain's subdomains and hosts.
Free
SecurityTrails
Historical DNS, WHOIS and subdomain data for domains and IP addresses.
Freemium
Subfinder
Fast passive subdomain discovery tool that enumerates valid subdomains for a domain.
Open source
ViewDNS.info
Collection of free DNS, WHOIS, reverse-IP and network lookup tools.
Free
Whoxy
WHOIS lookup and reverse-WHOIS history, including registrant-name search.
Freemium
crt.sh
Searches Certificate Transparency logs to enumerate a domain's certificates and subdomains.
Free
dnstwist
Generates and checks domain permutations to detect typosquatting and phishing lookalikes.
Open source