Discussions about denial of service revolve around networks. When someone mentions denial of service, it seems as though it’s common to envision a large flood of traffic of one sort or another. The problem is that there are a number of conditions that might cause a denial of service and not all of them are even malicious. Any event where an application that listens on the network becomes unavailable, you have a denial of service. You could argue that anytime an application becomes unavailable, whether it’s listening on the network or not, you have a denial of service.
by Ric Messier