3.3.b Implement and troubleshoot default routing

Administrator can configure a single default route to represent a path to any network that does not have a more specific match with another route in the routing table. Default routes are used to send traffic to any destination beyond the next upstream router.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 2645-2647).  . Kindle Edition.

http://www.cisco.com/c/en/us/td/docs/security/asa/asa82/configuration/guide/config/route_static.html