Open Port Check Tool
  - 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.

Your IP:
What Port?
Common Ports
Pop 3110
Other Applications
Remote Desktop3389
PC Anywhere5631


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. With blocked port 80 you will need to run your web server on a non-standard port in conjunction with a port 80/web redirect from

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. If you need to send legitimate email and your ISP blocks port 25. Consider the solutions 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, No-IP has a solution.

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