This page serves as a free utility for remotely verifying if 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.

Your Current Public IP Address is:

Common Ports
FTP 21
SSH 22
Telnet 23
Web 80
Pop 3 110
IMAP 143
Other Applications
Remote Desktop 3389
PC Anywhere 5631
Full Port List

Port Forwarding Facts:

  • Most residential Internet Service Providers (ISPs) block ports to combat viruses and spam. The most commonly blocked ports are port 80 (http traffic) and port 25 (SMTP: used for e-mail routing between mail servers).
  • Port 80 is the default port for http traffic. When port 80 is blocked, you will need to run your web server or device on a non-standard port in conjunction with a port 80/web redirect from This is typically port 8080.
  • 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 from within their network. If you would like to run your own email server and your ISP blocks port 25. Check out Alternate-Port SMTP from

Open Port Check tool is a free tool provided by If you are having problems with your ISP blocking ports including port 25 and port 80, NoIP has a solution.

Free Dynamic DNS - Port Check Tool