Senior Systems Engineer

Join our team at Core One! Our mission is to be at the forefront of devising analytical, operational and technical solutions to our Nation's most complex national security challenges. In order to achieve our mission, Core One values people first! We are committed to recruiting, nurturing, and retaining top talent! We offer a competitive total compensation package that sets us apart from our competition. Core One is a team-oriented, dynamic, and growing company that values exceptional performance!

The Senior Systems Engineer is responsible for building, securing, and sustaining the network and systems infrastructure that supports program and customer operations across on-premises, cloud, and hybrid environments. This role spans network configuration and troubleshooting, server and virtualization administration, and the security controls that protect both. The ideal candidate is a hands-on generalist who is comfortable owning a problem from diagnosis through implementation and documentation, works well alongside software engineers and field IT staff, and brings sound judgment to sensitive operating environments.

Network Infrastructure

• Configure, maintain, and troubleshoot enterprise network infrastructure including routers, switches, firewalls, and VPN connectivity.
• Support the design and implementation of LAN, WAN, and remote site network solutions that meet operational and security requirements.
• Analyze network performance data, identify inefficiencies, and recommend technical solutions to improve reliability and throughput.
• Serve as an escalation point for network faults, performing structured troubleshooting to restore service and document root cause.

Systems & Virtualization

• Administer physical and virtual server environments, including hypervisor management, operating system patching, and storage configuration.
• Perform system administration tasks such as user account management, access control, directory services, and backup and recovery.
• Plan and execute system and infrastructure upgrades, sequencing work to minimize disruption to ongoing operations.
• Support cloud and hybrid environments, including virtual networks, access controls, and connectivity between cloud and on-premises resources.

Security & Hardening

• Implement and maintain firewall rules, access control lists, and network segmentation in line with established security policy.
• Harden systems and network devices against established security baselines and support remediation of identified vulnerabilities.
• Support the Security Operations Center in investigating security events affecting network and system infrastructure.
• Apply cybersecurity best practices to day-to-day configuration and change activity.

Automation & Monitoring

• Develop scripts and automation to reduce repetitive configuration and administration tasks, using tools such as Python, PowerShell, or Ansible.
• Configure and maintain monitoring and alerting for network and system health, availability, and performance.
• Produce recurring reporting on infrastructure status and utilization for technical and program leadership.

Documentation & Collaboration

• Develop and maintain standard operating procedures (SOPs), network and system diagrams, configuration baselines, and troubleshooting guides.
• Collaborate with Software Engineers, Field IT staff, and other technical teams to translate operational requirements into working solutions.
• Provide technical guidance and cross-training to Technical Associates and junior staff.
• Stay current with emerging infrastructure technologies and security practices, and recommend adoption where they support mission objectives.

• Bachelor’s degree in Computer Science, Information Systems, or a related technical field OR 5+ additional years relevant experience in lieu of education.
• 5+ years of relevant systems and network engineering experience.
• Hands-on experience configuring and troubleshooting enterprise routing, switching, and firewall platforms.
• Experience administering Windows and Linux server environments and virtualization platforms.
• Working knowledge of cloud networking and hybrid connectivity in AWS or Azure.
• Proficiency with scripting and shell environments for automation and administration.

• Certifications such as CCNA, CCNP, Security+, or AWS Solutions Architect – Associate.
• Experience with air-gapped, isolated, or closed network environments in secure settings.
• Experience supporting secure communications and VTC infrastructure.
• Familiarity with infrastructure-as-code and configuration management practices.
• Experience supporting multi-site or distributed infrastructure.

• Broad technical depth across network, systems, and security domains
• Strong troubleshooting and root cause analysis skills
• Ability to work independently and manage competing priorities
• Disciplined change management and documentation practices
• Excellent written and verbal communication skills
• Willingness to cross-train and support adjacent technical disciplines

Based in Sterling, VA (Washington, DC metro area), with minimal travel to support client engagements.

Salary Range: $125,000-$165,000
The pay range reflected above is a general guideline for this position and labor category and is not a guarantee of a specific salary or offer. Final compensation is determined based on factors including, but not limited to, relevant experience, education, certifications, security clearance level, contract requirements, geographic location, and internal pay equity, and may reflect market data specific to the awarded contract.

Core One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, gender identity, sexual orientation, national origin, or protected veteran status and will not be discriminated against on the basis of disability.

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