System Administrator (TS/SCI Eligible) – Windows & Linux

Sigma Defense; March Air Reserve Base (CA); On-site; USD 115,000 - 135,000; Full time

Benefits offered by this job

Dental and Vision Insurance

Medical with HSA/FSA/DFSA

Life and AD&D coverage

Employee Assistance Program (EAP)

401(k) Plan with Company Matching

160 Hours PTO

12 Holidays

Educational Assistance

Highly Competitive Salary

Job summary

Sigma Defense is seeking a System Administrator to join our team at March Air Reserve Base. This role administers Windows and Red Hat Enterprise Linux environments, performs routine maintenance and patching, and ensures secure, reliable operations in coordination with engineering and cybersecurity teams.

The position requires 3–7 years of experience, Security+ certification, and US citizenship. Bachelor's degree in IT, familiarity with STIGs, CDS, FMV, and VMware ESXi preferred.

Qualifications

• 3–7 years of relevant experience.
• Experience administering Windows Server and/or RHEL 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 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.

Responsibilities

• 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.

Skills

Windows Server

RHEL

VMware ESXi

Bash

PowerShell

Ansible

Education

Bachelor's degree in Information Technology

Tools

Bash

PowerShell

Ansible

Job description

Sigma Defense is seeking a System Administrator to join our team at March Air Reserve Base. This role administers Windows and Red Hat Enterprise Linux environments, performs routine maintenance and patching, and ensures secure, reliable operations in coordination with engineering and cybersecurity teams.

The position requires 3–7 years of experience, Security+ certification, and US citizenship. Bachelor's degree in IT, familiarity with STIGs, CDS, FMV, and VMware ESXi preferred.