port. For example, to play a multiplayer game with friends online, you might need to open a port for the game so that the firewall allows the game information to reach your computer. A port stays open all the time, so be sure to close ports that you don’t need anymore.

Click to open Windows Firewall. In the left pane, click Advanced settings.

windows 7 advanced firewall

In the Windows Firewall with Advanced Security dialog box, in the left pane, click Inbound Rules, and then, in the right pane, click New Rule.

windows firewall rules

Follow the instructions on your screen. Sourced from Windows Help & Support.

Also see How to Manage Windows 7 Firewall & Five Tools for Managing Windows Vista Firewall.