text: Most businesses these days are connected to the internet and generally they are using permanently connected high speed lines.  The lines mean that your employees have fast access to the internet and email.\n\nA firewall is a computer that sits between your business computers and the computers on the internet.  It is designed to stop malicious data and people from getting into your business's private network.\n\nA firewall is normally configured to severely restrict access from the outside world, but let anything from the inside get out.  For example you probably want people to be able to connect to your web server and see your website.  You're probably less keen to let just anyone into your accounts server to see how you're doing!\n\nA firewall will\n- restrict outside access to your network to just the places you want other people to see\n- mitigate or prevent worms (think of it like a network based computer virus) from attacking and infesting your network\n- mitigate or prevent DOS (denial of service) attacks against your business network\n- allow you to restrict and control employees access to the internet (ie disallow applications you don't want your employees using, eg limewire or msn messenger)