Military OneSource is provided by the Department of Defense at no cost to active duty, Guard and Reserve (regardless of activation status) and their familiesEducation, relocation, parenting, stress  - Military OneSource is here to help you with just about any need. Available by phone or online, our free service is provided by the Department of Defense for active-duty, Guard, and Reserve service members and their families. The service is completely private and confidential, with few exceptions.