1773 - System Administrator
- Location
- March Air Reserve Base, California, United States
- Work mode
- On-site
- Employment type
- Full-time
About the job
Sigma Defense is seeking a System Administrator to join our team at March Air Reserve Base. This position plays a key role in maintaining secure Department of War information systems by administering Windows and Red Hat Enterprise Linux (RHEL) environments, performing routine maintenance and patching, and ensuring reliable system operations. The Systems Administrator works closely with the engineering and cybersecurity teams to maintain secure, stable, and mission-ready infrastructure supporting Department of War operations. Equal Opportunity Employer/Veterans/Disabled: Sigma Defense Systems is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability. Requirements
• 3-7 years of relevant experience.
- 3-7 years of relevant experience.
- Experience administering Windows Server and/or RHEL systems.
- Experience installing, configuring, maintaining, and troubleshooting server operating systems.
- Experience with virtualization technologies such as VMware ESXi.
- Experience performing operating system patching, maintenance, and lifecycle support.
- Basic understanding of networking concepts and enterprise infrastructure.
- Experience supporting secure or air-gapped Department of War environments.
- Experience with Cross Domain Solution (CDS) technologies.
- Experience with Full Motion Video (FMV) systems, platforms, or supporting infrastructure.
- Experience implementing or maintaining DISA Security Technical Implementation Guides (STIGs).
- Experience maintaining secure Windows and/or RHEL system baselines.
- Experience administering RHEL in physical or virtualized environments.
- Experience with storage, backup, and disaster recovery solutions.
- Must be a U.S. citizen.
• Security+ is required.
- Security+ is required.
- RHCSA is preferred.
- Network+ is preferred.
- Linux+ is preferred.
- Server+ is preferred.
• Experience with Bash, PowerShell, Ansible, or other scripting and automation tools.
- Experience with Bash, PowerShell, Ansible, or other scripting and automation tools.
• Candidate must possess or have the ability to obtain an active TS/SCI security clearance or higher.
- Candidate must possess or have the ability to obtain an active TS/SCI security clearance or higher.
- Clearance may be sponsored for the right candidate.
• Bachelor's degree from an accredited college or university in Information Technology or related field of study.
- Bachelor's degree from an accredited college or university in Information Technology or related field of study.
• Install, configure, maintain, and troubleshoot Windows and RHEL systems. • Perform routine operating system patching, software updates, and system maintenance. • Maintain physical and virtual server infrastructure. • Configure and maintain user accounts, storage, system services, and server resources. • Troubleshoot hardware, operating system, and application issues. • Support implementation of DISA STIGs and approved system configuration changes. • Maintain system documentation, configuration baselines, and standard operating procedures. • Support system backups, recovery operations, and disaster recovery activities. • Support secure Cross Domain Solution (CDS) operations and associated system administration activities. • Coordinate with cybersecurity and network engineering personnel to implement approved system changes and maintain secure, reliable system operations. • Support testing, integration, and implementation of approved hardware and software changes. • Monitor system health, investigate operational issues, and resolve problems to maintain system availability and performance. Salary Range : $115,000 - $135,000 annually. Benefits
- Dental and Vision Insurance
- Medical Insurance to Include HSA, FSA, and DFSA Plans
- Life and AD&D coverage
- Employee Assistance Program (EAP)
- 401(k) Plan with Company Matching Contributions
- 160 Hours of Paid Time Off (PTO)
- 12 (Floating) Holidays
- Educational Assistance
- Highly Competitive Salary
From Sigma Defense's careers page (Workable), checked 28 Oct 2026.
How to apply
- Select Apply on apply.workable.com. It opens Sigma Defense's own application form in a new tab, run on Workable.
- Fill in the form and upload your résumé there. Jobiwork never sees your application.
- Sigma Defense will reply to you directly. No real employer asks you for money to apply.
Posted 27 Oct 2026 · checked 28 Oct 2026 · Report this job