What is a firewall?
A firewall is a computer programme that blocks the gateway
between two networks - usually the private network of your computer and the
public network of the Internet. It blocks the channel to ensure that unwanted
visitors from the Internet can’t get into your private network. As a broadband connection is
effectively open 24 hours a day (regardless of whether your computer is
switched on), there’s a lot of time for someone to get into your personal files
if they want to, but a firewall makes that almost impossible.
The firewall does this by
filtering all the information that comes through your connection, as well as segmenting
your network into different physical sub-networks, limiting the damage that can
spread from one to the next. This is where the term comes from, as it works
like a fire door or firewall in the real world.
What are the different
types of firewall?
You can get a firewall as a piece of software or hardware.
As hardware, it’s usually part of a router which then connects to your home
network. If you don’t need a router, you’re probably better off installing firewall
software onto your main computer (any computer in your house that directly
receives a broadband signal). Some firewall software is free to download, but some more advanced
packages carry a charge.
Free firewall software:
- Windows built-in firewall – Basic software
- ZoneAlarm – Good software
Paid-for
firewall software:
- Norton Internet Security – Good, includes virus
scan
- McAfee Internet Security Suite – Good, includes
virus scan
- ZoneAlarm Internet Security Suite – More
advanced
- Panda Platinum Internet Security – Includes virus
scan
The easiest way to get a hardware firewall is through your broadband router. Some
routers have a built-in firewall (which you may have to enable yourself – your
instruction manual should tell you how to do this), including:
- Netgear
- Belkin
- Dlink
- Hayes
- LinkSys
- BT Voyager
- US Robotics.
Where can I buy a
firewall?
Firewalls, whether software or hardware,
are readily available now that more households are upgrading to broadband. Take a look at the listings above for information about where
you can pick up the relevant equipment.
How do I install a
firewall and change the settings?
If you opt for a hardware firewall, such as a router with
built-in firewall, your PC
security should become active when the device is connected. You may have to
enable the firewall separately – check your instructions for details.
If you’re installing
firewall software instead, you should be given an installation disc which will
take you through a step-by-step installation process. The firewall blocks
information passing both ways – from your network to the internet and from the
internet to your network. This means that you may have to enable some specific
"ports" in order to use applications like MSN Messenger.
Ports are virtual back
doors into a PC, and each computer has about 65,000 of them. Each one opens to
allow information to pass back and forth, and the firewall’s job is to keep
them closed, so you’ll need to open certain ones so that you can use your computer
normally. Once your firewall is in place, it will check any new equipment or
software that you install to make sure it’s no threat to your system. All being
well, it will open new ports to allow your new programs to work.
How do I protect a
wireless network?
To protect your wireless internet network, your first step should be enabling the built-in firewall in your
router, if there is one. There are various encryption methods to choose from,
whereby you can secure your network with a password. Without this type of security,
in theory someone with a laptop computer could stand outside your house and tap
into your home wireless
internet network. As long as you enable the security systems built into
your router, you should be safe from amateur hacking methods like this. Some
routers will also allow you to select a security measure called "wireless
isolation", which will cut your network off from other networks.
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