One of the most notorious excuses, used by many and accepted by few, is the passive rhetoric of “Mistakes were made.” Even when accompanied by context, when “bad things happen” we rarely know what the specific mistake was or who made the mistake. Mistakes, apparently, just happen. In network security, one of the biggest mistakes you can make that exposes your system to attack is forgetting to turn on a firewall.
This chapter covers network defenses such as firewalls and network monitors. Firewalls aren’t magic; using one doesn’t afford perfect protection to your system(s). However, not using a firewall potentially exposes ...