Home users will rely on the controls in their router or a software firewall on their computer, but for business users a proper firewall solution is required. The problem that arises especially for smaller businesses is the cost but there are free alternatives, one such product is Smoothwall Express. Smoothwall Express is a free firewall that includes its own security-hardened GNU/Linux operating system and an easy-to-use web interface. I have it running in a live environment for over a year now and it is very stable. All you need to get started is an old desktop, at least two network cards but preferably three, and a download of Smoothwall.
When documenting changes to the network infrastructure I feel that a diagram is nearly always necessary to allow support staff to fully understand the system. My preferred application is MS Visio which has a wealth of options for creating diagrams including UML, floor plans, network diagrams and more. You can quickly and easily create very professional looking documentation. I am lucky that my organisation provides Visio as it is expensive to purchase as an individual, so I was interested to come across a free alternative called Dia.