Administer and maintain enterprise Windows infrastructure, including Windows Server, Active Directory, Group Policy, DNS, DHCP, Public Key Infrastructure (PKI), virtualization platforms (VMware vSphere and Hyper-V), and supporting services to ensure system reliability, availability, and performance. Manage enterprise authentication and security services, including RSA SecurID multifactor authentication (MFA), authentication policies, token administration, security patching, vulnerability remediation, and DISA Security Technical Implementation Guide (STIG) compliance.