The primary purpose and the major responsibility of the Department of defense is the security of the homeland against external risks and threats. It also is responsible for preventing attacks on the homeland, its territories, and the assets of the country (Goss, 2006). But to ensure that they provide tight security to the nation and their strategies don’t fail they need a defense that is focused externally, prompt, and finds issues related to the homeland at the source of the threat. But every threat cannot be prevented therefor