The U.S. Cyber Command (CYBERCOM) hosted its first tactical-level exercise focusing on national defensive cyberspace operations. CYBER GUARD included nearly 500 participants representing the National Security Agency (NSA), the National Guard, the U.S. Department of Homeland Security (DHS) and the FBI. The cyber subject matter experts focused on national defensive cyberspace operations; command and control with mission integration between CYBERCOM/NSA; and the National Guard also was addressed in a joint dynamic cybertraining environment. Conducted at Fort Meade, the week-long event enabled participants to practice fully coordinated defensive response actions and mitigation measures in a homeland security scenario, which took place in a virtual environment on a closed cyber range. CYBER GUARD allowed the command to practice and institutionalize processes and procedures while establishing a framework for future operational urgent requirements. One goal of the event was to create U.S. Defense Department and NSA relationships with the Guard to increase cyberspace capability and situational awareness in support the the DHS' and FBI's effort titled "Defense of the Nation."