Senior VMware & Systems Admin — Secure Infra & Networking

AMERICAN SYSTEMS; Arlington (VA); On-site; USD 110,000 - 150,000; Full time

Job summary

AMERICAN SYSTEMS in Arlington, VA is seeking a Sr. Systems Administrator to support, maintain, secure, and optimize enterprise IT systems with a strong focus on network infrastructure, switching, and VMware virtualization.

The role requires hands-on management of servers, virtual environments, AD, DNS, DHCP, security controls, and patching, with TS clearance and CompTIA Security+ certification preferred.

Qualifications

• Active Top Secret clearance with SCI eligibility.
• CompTIA Security+ certification.
• 3+ years of experience in systems administration, network administration, or cyber infrastructure support.
• Hands-on experience with managed network switches and enterprise networking concepts.
• Strong experience with VMware vSphere, including ESXi and vCenter administration.
• Experience with Windows Server administration and core services such as Active Directory, DNS, DHCP, and Group Policy.
• Understanding of cybersecurity principles, system hardening, patching, vulnerability management, and secure access controls.
• Experience troubleshooting network connectivity, switching, and virtualization issues.

Responsibilities

• Administer, maintain, and troubleshoot enterprise IT infrastructure, including servers, virtual environments, and network systems.
• Configure, manage, and support network switches, VLANs, trunking, port security, and related network services.
• Monitor and maintain LAN/WAN connectivity, network performance, and infrastructure availability.
• Deploy, administer and support VMware environments, including ESXi hosts, vCenter, virtual machines, storage connectivity, snapshots, patching, and performance tuning.
• Implement and maintain secure system configurations in accordance with company cybersecurity policies and best practices.
• Perform system hardening, patch management, vulnerability remediation, and access control administration.
• Support firewall, VPN, endpoint protection, and network access controls as needed.
• Manage Active Directory, group policies, DNS, DHCP, and other core infrastructure services.
• Respond to system alerts and outages; conduct root cause analysis and document corrective actions.
• Support backup, disaster recovery, and business continuity processes for critical systems.
• Maintain system documentation, network diagrams, standard operating procedures, and asset inventories.
• Assist with audits, compliance activities, and security assessments.
• Collaborate with IT, cybersecurity, and business teams on infrastructure upgrades, deployments, and operational improvements.
• Recommend improvements to system performance, reliability, and security posture.

Skills

Analytical problem-solving

Security-minded mindset

Independent work

Team collaboration

Education

Bachelor's degree in Information Technology, Cybersecurity, Computer Science, or related field

Tools

VMware ESXi

VMware vCenter

Windows Server

Active Directory

DNS

Job description

AMERICAN SYSTEMS in Arlington, VA is seeking a Sr. Systems Administrator to support, maintain, secure, and optimize enterprise IT systems with a strong focus on network infrastructure, switching, and VMware virtualization.

The role requires hands-on management of servers, virtual environments, AD, DNS, DHCP, security controls, and patching, with TS clearance and CompTIA Security+ certification preferred.