Whoisology - Connected database of whois records and whois history
IP-Toolbox.com - IP-Toolbox.com is the best site for quick and easy viewing of your public IP address and other related information.
WhoisThisDomain - Domain name lookup tool that allows you to get information about domain registration from WHOIS server.
What is My IP Live - Find your IPv4 and IPv6 just by visiting whatismyip.live - complete IP geolocation is also provided along with some other useful IP tools.
JSON WHOIS API - Parsed domain WHOIS data from any WHOIS server via RESTful API with metered pay as you pricing.
GRC Port Scan - GRC Internet Security Port Scanner. Tests for open ports on your external IP address.