ManTech seeks a motivated, mission-oriented Senior Systems Administrator to join our team in Chantilly, VA. As the Senior Systems Administrator, you will be responsible for providing a full range of Tier 2/3 IT support services and expertise to customer activities. You will play a key role in the management, optimization, and troubleshooting of our VMware virtualized environment and Active Directory infrastructure, ensuring seamless and reliable operations for the organization. You will demonstrate knowledge and understanding of client and server operations and maintenance with Windows 10 and 11 environments and Windows Server 2016/2019, to include Active Directory, Domain Controllers, DNS, GPO’s, PKI, DHCP, VMware v8, Backup Architectures, Storage Management, and Auditing. **Responsibilities include, but not limited to:** + Design, implement, and maintain VMware vSphere environments, including vCenter, ESXi hosts, and virtual machines. + Troubleshoot and resolve VMware-related issues, including performance bottlenecks, connectivity problems, and resource allocation. + Manage, monitor, and troubleshoot Active Directory (AD) and Group Policy infrastructure. + Administer and support user and group management, including security and distribution groups within Active Directory. + Collaborate with other IT teams to manage system integration, configuration, and upgrades. + Create and maintain comprehensive documentation for systems architecture, processes, and configurations + Domestic Travel up to 25% **Minimum Qualifications:** + Bachelor’s Degree and 7 years’ experience, or high school diploma/GED and 13 years of relevant systems administration experience + Experience in performing maintenance, repair, upgrade, and full life cycle support of hardware/software interfacing with the enterprise + Knowledge of Windows file and folder permission & inheritance structure + Experience in researching and ordering hardware/software to meet customer requirements + Experience with client system security to include scans, patching, audit log review, and system health checks + Provide leadership and mentoring to junior administrators and technical support + Security+ certification (active) **Preferred Qualifications:** + Previous NRO and NRO/COMM experience is highly desired + COMSEC experience desired + Awareness of new technologies and methods that could improve current environment + Familiarity with PowerShell + Experience with Microsoft Exchange + Experience with Linux + Ability to use MS Office and PC **Clearance Requirements:** + Must possess a current / active TS/SCI with Polygraph **Physical Requirements:** + Must be able to be in a stationary position more than 50% of the time + Needs to occasionally move about inside the office to access file cabinets, office machinery, etc. + Frequently communicates with co-workers, management, and customers, which may involve delivering presentations + Frequently moves Audio/Visual or Computer equipment weighing up to 50 pounds across and/or around a business campus or large facility ManTech International Corporation, as well as its subsidiaries proactively fulfills its role as an equal opportunity employer. We do not discriminate against any employee or applicant for employment. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, or status as a protected veteran. If you are a qualified individual with a disability and require a reasonable accommodation to apply for a position with ManTech through its online applicant system, please email us at careers@mantech.com and provide your name and contact information.