Senior Network Systems Engineer - Onsite TS/SCI Clearance

Gentry Professional Services, Inc.; San Antonio (TX); On-site; USD 140,000 - 210,000; Full time

Benefits offered by this job

401(k) with 4% match

Health insurance

Dental insurance

Vision insurance

HSA

Job summary

Gentry Professional Services seeks a Senior Principal Network Systems Engineer to architect and sustain high-availability launch and test networks for classified and unclassified enclaves in the San Antonio area. The role requires TS clearance with SCI eligibility and hands-on expertise across routers, switches, firewalls, and related security controls.

You will lead design, testing, and implementation plans, coordinate with ISSMs/ISSOs, and drive RMF-aligned protections while embedding security

Qualifications

• U.S. citizenship with active DoD Top Secret clearance and SCI eligibility/access within the last 24 months.
• DoD 8570 IAT Level II certification or equivalent prior to start.
• Hands-on experience planning, implementing, operating, and troubleshooting routed and switched IP networks (IPv4, OSPF, VLANs, VPNs, firewalls).
• Strong collaboration with cyber teams and ISSMs/ISSOs to maintain RMF-aligned protections.

Responsibilities

• Design, plan, configure, and sustain complex, multi-node networks spanning classified and unclassified enclaves with detailed schematics for routers, switches, firewalls, and gateways.
• Lead end-to-end testing and validation, verify configurations, and monitor performance for reliability and security policy compliance.
• Develop and execute implementation plans for enhancements, upgrades, and migrations while coordinating with stakeholders to minimize disruption.
• Engineer and operate core network services (DNS, DHCP, NTP, AAA) and segmented architectures with trusted boundaries across enclaves.
• Implement and tune network security controls (firewalls, VPNs, ACLs, IDS/IPS, NAC) in coordination with cyber teams.
• Support NOC/SOC operations with fault and performance monitoring, incident response, and change management.

Job description

Gentry Professional Services seeks a Senior Principal Network Systems Engineer to architect and sustain high-availability launch and test networks for classified and unclassified enclaves in the San Antonio area. The role requires TS clearance with SCI eligibility and hands-on expertise across routers, switches, firewalls, and related security controls.

You will lead design, testing, and implementation plans, coordinate with ISSMs/ISSOs, and drive RMF-aligned protections while embedding security