Whoisology - Connected database of whois records and whois history
GRC Port Scan - GRC Internet Security Port Scanner. Tests for open ports on your external IP address.
WhoisThisDomain - Domain name lookup tool that allows you to get information about domain registration from WHOIS server.
What is my IP? - Find out what your IP is. Do not hesitate to open wimip.
Bulk Whois API - Bulk Whois API is a provider of parsed WHOIS data in JSON with simple API, competitive pricing, top notch support, and more.
whatismyip.cc - External IP Address lookup tool with option to scan the external IP address.