Installing/Configuring a Firewall

Firewalls are used to monitor and control which connections can be made to and from your PC over the network. Done correctly, this will help protect unauthorised access to your PC and your data.

Firewalls can cause problems for some applications that try to connect to other computers, so it is important that you understand what you are doing when you install one.

Microsoft Windows XP SP3

The Microsoft Windows XP firewall is a one-way firewall can be configured as follows:

• Click on Start
• Click on Control Panel
• Click on Windows Firewall
• Select the Exceptions tab and you'll see something like this:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Windows XP one-way firewall automatically allows all outgoing connections (from your PC to somewhere else), but will block all incoming connections which are not ticked on this list.

Microsoft Windows Vista and Windows 7 Firewall

The Microsoft Windows Vista/7 firewall is a two-way firewall and is configured rather differently to XP. In addition, even though the Vista and 7 firewalls look the same, they don't behave the same.

To configure your incoming firewall rules:

• Click on Start
• Click on Control Panel
• Click on Windows Firewall

Select Allow a program or feature through Windows Firewall (at the top left) and you'll see something like this:

 

 

 

 

 

 

 

 

 

 

 

The firewall will be greyed out until you press the Change settings button. It then behaves in a similar manner to the XP firewall, only now you have to choose which of the three firewall profiles you want your exception to be allowed in (you have to tick the name and at least one of the three profiles in order to allow the program through).

There is now one further complication: what happens if you're connected to two networks at once (i.e. a wired connection to a domain network and a wireless connection to a public network)? What happens next depends on whether you're running Vista or 7:

Running Vista: the most secure rule from both profiles is applied to the program for both connections

Running 7: each connection keeps its own rule for the program

Configuring Windows Vista / Windows 7 outgoing rules

As mentioned above, later versions of Windows use a two-way firewall, i.e. it also blocks outgoing connections from your PC. You can edit outgoing rules by opening Windows Firewall with Advanced Security from your Administrative Tools menu (or type WF.msc in your Search programs and files menu to run it directly).

With this tool, you will able to configure your incoming and outgoing rules separately for each profile. It is beyond the scope of this guide to discuss advanced firewall configuration and the reader is referred to the many online guides.