Secure Systems Administrator: Windows & Linux (TS/SCI)

Sigma Defense; California, Northern (MO, KY); Hybrid; USD 115,000 - 135,000; Full time

Benefits offered by this job

Dental and Vision Insurance

Medical Insurance with HSA/FSA/DFSA

Life and AD&D coverage

Employee Assistance Program (EAP)

401(k) Match

Paid Time Off (PTO)

Holidays

Educational Assistance

Competitive Salary

Job summary

Sigma Defense is seeking a System Administrator to join our team at March Air Reserve Base. The role focuses on maintaining secure Windows and Red Hat Enterprise Linux environments, applying patches, and ensuring mission-ready infrastructure.

Responsibilities include operating system maintenance, configuration, backups, and disaster recovery, with emphasis on secure CDS/FMV operations and collaboration with cybersecurity teams.

Qualifications

• 3–7 years of relevant experience in system administration.
• Experience with Windows Server and/or RHEL environments.
• Experience installing, configuring, maintaining, and troubleshooting server OS.
• Experience with virtualization technologies such as VMware ESXi.
• Knowledge of patching, updates, and lifecycle management.
• Familiarity with networking concepts and enterprise infrastructure.
• Experience with secure DoD environments and CDS/FMVs.
• Experience implementing DISA STIGs and secure baselines.
• Experience with storage, backup, and disaster recovery systems.

Responsibilities

• Install, configure, maintain, and troubleshoot Windows and RHEL systems.
• Perform routine OS patching, software updates, and system maintenance.
• Maintain physical and virtual server infrastructure.
• Configure and maintain user accounts, storage, services, and resources.
• Troubleshoot hardware, OS, and application issues.
• Support DISA STIGs and approved configuration changes.
• Maintain system documentation and standard operating procedures.
• Support backups, recovery operations, and disaster recovery activities.
• Support secure CDS operations and related administration.
• Coordinate with cybersecurity and network teams for changes and operations.
• Assist testing, integration, and implementation of approved changes.
• Monitor system health and resolve issues to ensure availability.

Skills

Windows/RHEL Admin

VMware ESXi

Patching & Maintenance

Networking basics

Security/STIGs

CDS & FMV

Scripting (Bash/PowerShell/Ansible)

Backup & DR

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. The role focuses on maintaining secure Windows and Red Hat Enterprise Linux environments, applying patches, and ensuring mission-ready infrastructure.

Responsibilities include operating system maintenance, configuration, backups, and disaster recovery, with emphasis on secure CDS/FMV operations and collaboration with cybersecurity teams.