Tier 2 Systems Administrator

Job Title: Tier 2 Systems Administrator
Job Category: Information Technology
Time Type: Full time
Minimum Clearance Required to Start: TS/SCI with Polygraph
Employee Type: Regular
Percentage of Travel Required: None
Type of Travel: None
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The Opportunity
CACI is seeking an experienced, hands-on Tier 2 Systems Administrator to support mission-critical IT infrastructure and applications in a secure, 24×7 operational environment.
This position serves as a technical escalation point for Tier 1 operations personnel and is responsible for administering, maintaining, monitoring, and troubleshooting enterprise infrastructure, including Linux/Unix and Windows servers, virtual environments, network connectivity, storage, hardware, and custom mission applications.
The ideal candidate possesses a strong technical foundation across multiple infrastructure technologies and demonstrates the ability to independently investigate, isolate, and resolve unfamiliar technical issues. Success in this role requires more than routine system monitoring, ticket management, or following established procedures. We are looking for a technically capable problem-solver who can apply systems administration knowledge, critical thinking, and sound troubleshooting methodologies to maintain system availability and support mission operations.
Responsibilities
Administer, maintain, and troubleshoot Linux/Unix and Windows Server operating systems and associated infrastructure supporting mission-critical applications and services.
Serve as a Tier 2 escalation resource for technical issues involving servers, operating systems, custom software applications, virtualization, network connectivity, databases, storage, and hardware.
Independently investigate and troubleshoot unfamiliar technical issues by analyzing system logs, processes, services, configurations, resource utilization, network connectivity, and application dependencies.
Administer and troubleshoot VMware virtual environments, including virtual machines, resource allocation, storage, network connectivity, and system performance.
Perform routine system health checks, monitor system availability and performance, investigate alerts, and take corrective action to maintain operational readiness.
Troubleshoot Windows Server infrastructure, including Active Directory, DNS, Group Policy, authentication, permissions, and associated system services.
Support Linux/Unix system administration activities, including command-line troubleshooting, process and service management, log analysis, file permissions, and operating system maintenance.
Diagnose and resolve network connectivity and performance issues, including TCP/IP, DNS, routing, switch connectivity, firewall-related issues, and system communication dependencies.
Perform operating system patching, security updates, vulnerability remediation, system configuration changes, and routine maintenance in accordance with established security requirements.
Monitor backup processes, support restoration activities, and assist with maintaining system recoverability and data integrity.
Support physical infrastructure maintenance, hardware troubleshooting, server deployments, system upgrades, and new infrastructure projects.
Coordinate with Tier 1 operations personnel, engineering teams, network administrators, software developers, and other technical stakeholders to investigate and resolve incidents affecting mission operations.
Document troubleshooting actions, incident resolutions, configuration changes, technical findings, and system procedures using established ticketing and knowledge management systems.
Support user account administration, access controls, workstation troubleshooting, and peripheral equipment as operationally required.
Identify recurring technical issues, recommend corrective actions, and contribute to improvements in system reliability, operational efficiency, and support procedures.
Qualifications
Required:
Active TS/SCI clearance with polygraph.
DoD IAT Level II certification, such as CompTIA Security+ or an approved equivalent.
Minimum of 3 years of hands-on experience administering, maintaining, and troubleshooting enterprise servers, operating systems, and supporting IT infrastructure in a production environment.
Strong working knowledge of Linux/Unix operating systems, including command-line administration, system services, processes, logs, file permissions, and operating system troubleshooting.
Hands-on experience administering and troubleshooting Windows Server environments, including Active Directory, DNS, Group Policy, authentication, and system services.
Practical experience with VMware virtualization technologies, including virtual machine administration, configuration, and troubleshooting.
Working knowledge of networking fundamentals, including TCP/IP, DNS, routing, ports, network connectivity, and performance troubleshooting.
Demonstrated ability to independently investigate, isolate, and resolve technical issues involving multiple infrastructure components, operating systems, or custom software applications.
Experience performing system monitoring, routine health checks, operating system patching, security maintenance, and incident resolution.
Strong understanding of cybersecurity best practices, system hardening, access controls, and data protection.
Ability to work independently with general supervision, prioritize technical issues, and coordinate effectively with other technical teams.
Strong analytical, problem-solving, communication, and technical documentation skills.
Flexibility to work varying full-time schedules within the hours of 7:00 AM–6:00 PM, based on operational requirements, and participate in an after-hours on-call support rotation.
Ability to work onsite in Springfield, Virginia.
Desired:
Previous experience supporting mission-critical infrastructure, real-time operations, or 24×7 production environments.
Experience troubleshooting proprietary or custom-developed software applications, including application services, logs, interfaces, and supporting system dependencies.
Experience administering or troubleshooting Solaris or other Unix operating systems.
Knowledge of scri