The common features / benefits of firewalls:
- block unwanted incoming traffic to your network
- block outgoing network traffic based on source of destination ie. You may want to prevent employees from accessing certain web sites
- block network traffic based on content ie integrating with a virus scanner to prevent files or emails with viruses from entering your network
- allowing access to your network and internal resources to selective users
- allowing connection to internal network with a virtual private network (VPN). VPNs allow secure connection from the internet to a corporate network ie allowing staff to work from home
- allowing the ability to monitor traffic on the network.
Generally a firewall is installed where your internal network connects to the Internet. However, some large scale organisations also use them between different parts of their own network to provide different levels of security. An organisations Firewall can be a piece of hardware or software.
Commercial Networks have installed Hardware Firewalls for many of their customers and recommend Watchguard for being robust and easy to manage. The cost for what theoretically looks like a small box is minor compared to having hackers get onto your network.