WhoisXML API - Domain, IP, and DNS data provider
What is my IP? - Find out what your IP is. Do not hesitate to open wimip.
Oribi - Analytics for marketing & product teams
GRC Port Scan - GRC Internet Security Port Scanner. Tests for open ports on your external IP address.
Antideo - Email, IP address and phone number validation API service
TrueIP - TrueIP is a small program that runs in the system tray, monitoring your IP address(es).