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.