How to open firewall ports in Windows Firewall

It is rare that you should need to manually open a firewall port in Windows Firewall. Usually, when you install a new program and use it for the first time, Windows will offer to add a firewall exception or will trigger a permissions popup the first time the program tries to access the internet.

It is occasionally necessary to do it manually though. As it isn’t something you have to do very often, it isn’t something we remember how to do. That is what prompted this blog post.

What is a firewall?

A firewall is a piece of software installed in Windows, as a third party application or within your router firmware. There are also hardware firewalls but they are mainly for larger businesses.

The job of a firewall is to control what comes into your network and what can leave it. The software will inspect every packet that is due to be sent or received by your computer and compares it to a list of rules. If the program is allowed to communicate with the internet, the traffic is allowed through. If the program isn’t on the list, you will be prompted to add it or the firewall will tell your network card to ignore the traffic.

Open a firewall port in Windows Firewall

A port is a gateway into your computer that internet traffic can take. Different programs use different ports so the traffic knows where to go. For example, HTTP or browser traffic uses port 80, so your browser knows to listen on port 80 for the data it has asked for. IMAP uses port 143 so your email program knows to listen on that port for email traffic.

There are dozens of common ports in use within Windows and other games and programs use them too. The default ports are handled automatically or you will be prompted to either allow, or disallow traffic through the firewall. To manually open a port, do this:

  1. Navigate to Control Panel, System and Security and Windows Firewall.
  2. Select Advanced Settings and highlight Inbound Rules in the left pane.
  3. Right click Inbound Rules and select New Rule.
  4. Add the port you want to open and select Next.
  5. Add the protocol (TCP or UDP) and the port number into the next screen and select Next.
  6. Select Allow the connection in the next screen and select Next.
  7. Select the network type and select Next.
  8. Give the rule a name and select Finish.

I tend to suggest calling the rule by the name of the program to help identification. If something goes wrong or you need to troubleshoot, know what port is open for what program really helps.

The computer repair guys at Dave’s Computers in New Jersey can help with any computer or networking issue you may have. Bring your computer to our store and we will see what we can do!