North Dakota State University

This document tells you how to open a port in the Windows XP Firewall (for computers installed with Service Pack 2 only).  Opening a port may be necessary in order to allow programs to function properly.

Microsoft has a help document to tell you how to open a port in the Windows XP SP2 firewall located at http://support.microsoft.com.  You can read that document, or continue here for additional information specific to NDSU applications.

What is a firewall?

How to open a port (hole)?

First, it is important to understand what a firewall is and why it should be enabled.

According to developer.apple.com, a software firewall is "Software (or a computer running such software) that prevents unauthorized access to a network, by users outside of the network. (A physical firewall prevents the spread of fire between two physical locations; the software analog prevents the spread of unauthorized data). "

Simply put, a firewall protects a computer from programs (intruders) that seek unauthorized data and from programs (intruders) that aim to damage data.  By opening only the ports absolutely necessary for applications to function, a computer is more secure than if opening all ports.

With the software firewall enabled, certain programs that require access to the Internet may fail if the software firewall does not allow them to connect.  The solution to this is to open a port, or a "hole," in the firewall.

How to open ports:

Method 1 -

As was covered in the Windows XP SP2 document, you may receive security notices asking whether you would like to unblock a program.  This is the easiest method to use for allowing programs to access the Internet since it does not require you to do any additional steps after clicking "Unblock."

One common program that requires a port to be opened in the Windows XP Firewall is the ZENworks client (installed on ITS-supported computers).  Help Desk staff can not connect to a computer if the firewall port has not been opened.  Here's how:

Method 2-

1. In this case, manual configuration of the firewall is necessary.
2. Go to the Start Menu > and click Control Panel (if you have the classic Start Menu, click Start > Settings > Control Panel).
3. In the Control Panel, double-click on the Windows Firewall.
4. In the Windows Firewall window, click on the Exceptions tab.
5. On the Exceptions tab, click Add Port.
6. In the Add a Port window, type a name for the port you would like to add in the Name box (something you will recognize, such as ZENworks for ZENworks, or Calendar for Calendar.  The name is not important to functionality).
7. Enter the port number in the Port number box.
   1. For ZENworks, this is port 1761.
8. Check the radio button for the network protocol that should be opened.
1. For ZENworks, this is TCP.

The port will now be listed in the Programs and Services exception list and (hopefully) the program will function as expected. 

Occasionally, more than one port is required to be open in order for a program to work.  In this case, repeat these steps for each port.

**Additional methods are covered in the Microsoft Help document, linked at the top of the page.

**The Microsoft help document, linked at the top of the page, also covers how to discover what port number should be unblocked if it is not already known.

jillande