HostedScan.com - Online vulnerability scanner for servers, networks, and web applications.
GRC Port Scan - GRC Internet Security Port Scanner. Tests for open ports on your external IP address.
HackerTarget.com - Security Vulnerability Scanning based on Open Source Tools.
What is my IP? - Find out what your IP is. Do not hesitate to open wimip.
Intruder - Intruder is a security monitoring platform for internet-facing systems.
whatismyip.cc - External IP Address lookup tool with option to scan the external IP address.