Whereas, you have to know every hole and gap in your armor, they only need to work hard enough to find one. It's time to take on the fortress mentality as your info systems sail off into dangerous and uncharted waters. Defense in Depth has been a concept pioneered by the Navy using assets in a battle group to best project their force outward in the most effective manner, while overlapping their coverage with various other units, to provide complete and redundant protection of the entire force. But the key to applying this defense is understanding its application and what you can be doing to support it today. Throughout history defense has started with a good wall and guards to watch them.
Networks are no exception.
Firewalls are now prevalent throughout the public and private sectors. Mere existence of a firewall does not mean you're safe for the night. Firewalls, like any other software, require updates, as well as proper configuration. Additionally, more and more firewalls are hitting the streets requiring patches and manual adjustments to prepare them for proper defense. The IDSs help provide the key indications of where the attack is focused, how to block the attack, and learn where to shore up your defenses.