Open a port in Windows Firewall

If Windows Firewall is blocking a program and you want to allow that program to communicate through the firewall, you can usually do that by selecting the program in the list of allowed programs (also called the exceptions list) in Windows Firewall. To learn how to do this, see Allow a program to communicate through Windows Firewall.

However, if the program isn't listed, you might need to open a 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 open anymore.

1. Click to open Windows Firewall.

2. In the left pane, click Advanced settings. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.

3. 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.

4. Follow the instructions in the New Inbound Rule wizard.

Risks of allowing programs through a firewall

When you add a program to the list of allowed programs in a firewall, or when you open a firewall port, you allow a particular program to send information to or from your computer through the firewall. Allowing a program to communicate through a firewall (sometimes called unblocking) is like punching a hole in the firewall.

Each time you open a port or allow a program to communicate through a firewall, your computer becomes a bit less secure. The more allowed programs or open ports your firewall has, the more opportunities there are for hackers or malicious software to use one of those openings to spread a worm, access your files, or use your computer to spread malicious software to others.

It's generally safer to add a program to the list of allowed programs than to open a port. If you open a port, it stays open until you close it, whether or not a program is using it. If you add a program to the list of allowed programs, the "hole" is open only when needed for a particular communication.


To help decrease your security risk:

1. Only allow a program or open a port when you really need to, and remove programs from the list of allowed programs or close ports that you no longer need.

2. Never allow a program that you don't recognize to communicate through the firewall.

Firewall

A firewall is software or hardware that checks information coming from the Internet or a network, and then either blocks it or allows it to pass through to your computer, depending on your firewall settings.

A firewall can help prevent hackers or malicious software (such as worms) from gaining access to your computer through a network or the Internet. A firewall can also help stop your computer from sending malicious software to other computers.

View and edit advanced firewall options

• You must be logged on as an administrator to perform these steps.
• Windows Firewall with Advanced Security is a Microsoft Management Console (MMC) snap-in that provides more advanced options for IT professionals. With this firewall, you can set up and view detailed inbound and outbound rules and integrate with Internet Protocol security (IPsec).

Follow these steps to open Windows Firewall with Advanced Security:

• Click to open Windows Firewall.
• In the left pane, click advanced settings. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
• Note: You must be a member of the Administrators group or the Network Operators group to use Windows Firewall with Advanced Security.