Grc.com - GRC | ShieldsUP! — Service Ports Probe
GRC Internet Security Detection System. The Internet's quickest, most popular, reliable and trusted, free Internet security checkup and information service. And now in its Port Authority Edition, it's also the most powerful and complete. Check your system here, and begin learning about using the Internet safely.
Gwebtools.com - On-Line Port Scanner - Check if your network ports are open
Make a on-line port scan testing your firewall security and checking if the ports in your computer are open or closed for access over internet.
Canyouseeme.org - Open Port Check Tool
This page will serve as a free utility for remotely verifying a port is open or closed. It will be useful for users who wish to check to see if a server is running or a firewall or ISP is blocking certain ports. Most residential ISP's block ports to combat viruses and spam. The most commonly blocked ports are port 80 and port 25. Port 80 is the default port for http traffic. Port 25 is the default port for sending and receiving mail. ISPs block this port to reduce the amount of spam generated by worms on infected machines within their network.
T1shopper.com - Online Port Scan | Port Scanning | Port Scanner | Port Checker
Web-based port scanning service to test your firewall or other devices.
Yougetsignal.com - Open Port Check Tool - Test Port Forwarding on Your Router
The port forwarding tester is a utility used to identify your external IP address and detect open ports on your connection. This tool is useful for finding out if your port forwarding is setup correctly or if your server applications are being blocked by a firewall.
My-addr.com - check open ports,check for listening ports tool,domain/hostname/IP/URL
On this page you can check opened ports of domain/hostname/IP, it's the same as check listening of ports. This tool trying to create port connection, connection timeout is 4 sec.
Hashemian.com - TCP/IP Port Scanner
TCP/IP port scanner, Internet scanner, vulnerability, probe server, network port scanner
Easy to use web-based port check service. Port check - Tests if port is opened on specified IP.
Webtoolhub.com - Online Port Scanner - Check Open Port - Scan Port
Free and powerful TCP port scanning tool to scan your firewall and other computer devices for open ports.
Subnetonline.com - SubnetOnline.com - Online Port Scanner
Online Port Scanner allows you to check a host or IP for an open or listening port.