Validatek is seeking a Senior Systems Administrator to join our mission-focused IT Operations team supporting Department of Defense (DoD) customers. This role is responsible for the administration, security, and reliability of enterprise Windows-based systems , ensuring compliance with DoD cybersecurity and operational standards. The ideal candidate is a hands-on technical expert with deep experience in Active Directory, DNS, DHCP, Group Policy, MS SQL , and SMB file shares , capable of managing large, complex environments with precision and accountability.