2. Protecting your computer: internet firewall, antivirus

2.1. Firewall

A firewall is a piece of equipment (hardware or software) that creates a protective wall between your computer and the internet. It can protect your computer from many hackers and computer viruses and worms.

What a firewall can and cannot do:

Can

  • Protect against Internet viruses, worms that try to infiltrate your computer from the Internet
  • Protect against hackers attacking your computer
  • Prevent unwanted programs from sending information from your computer

Cannot

  • Protect against computers that you consider trustworthy (e.g. a neighbouring computer on your local network)
  • Protect against internet viruses, worms that you receive via email, browser or other applications

Warning! It is not recommended to connect your computer to a network (the Internet) without first protecting it with a hardware or software firewall.

 

Hardware firewall

It is recommended to protect the local network with a special device called a hardware firewall. This device should prevent any connections from the Internet to work computers. This function can be performed by:

  • A specialised device that performs only firewall functions
  • A network router or wireless access point with the ability to filter network traffic.
  • A device (server) that performs internal network address translation functions.
Software firewall

Even if your local network is protected by a hardware firewall, do not overlook the dangers that come from the same local network. This could be a hostile neighbour, a colleague or a computer virus. A software firewall (Windows Firewall) installed on your computer can protect you from such problems.

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Location of the firewall in the computer network

 
Firewall or firewall functions
  • Blocks external connections to applications that only need to communicate within the local network (e.g. a database server on the local network).
  • Depending on sophistication, can protect against a variety of TCP protocol attacks if attacked from outside the firewall.
  • Can specifically identify and block packets sent by some common viruses or worms.
  • Can block Internet servers or network services (say, Skype) if connections to them are unwanted on this network.