Network Security Engineer, Lead

AMERICAN SYSTEMS is seeking a Lead Network Security Engineer to support a critical national security mission in a highly classified environment. This role combines hands-on enterprise network security with technical leadership across network, firewall, and access control capabilities, including Cisco security tooling.

Based in Dallas, TX with onsite support, you will design, implement, administer, and troubleshoot enterprise network and firewall/security controls, while helping drive secure, resilient outcomes for mission operations.

What you will do

• Provide secure network engineering, administration, and operational support in a highly classified environment.
• Design, implement, configure, and maintain enterprise network infrastructure including routers and switches, firewalls, VLANs, ACLs, VPNs, network segmentation, and high-availability architectures.
• Administer, monitor, and troubleshoot enterprise firewall environments.
• Configure and manage firewall policies, access rules, NAT, VPNs, security zones, logging, and monitoring.
• Support and troubleshoot Cisco Firepower and Firepower Management Center (FMC) capabilities (Cisco Firepower experience preferred).
• Troubleshoot complex Layer 2 and Layer 3 networking, routing, switching, firewall, connectivity, and access control issues.
• Support AAA and network access control requirements, including authentication, authorization, and accounting.
• Configure and troubleshoot 802.1X, VPN, and network access control solutions.
• Support Cisco ISE environments, including authentication, authorization, policy enforcement, and network access control (Cisco ISE experience preferred).
• Support RMF, STIG, secure configuration, vulnerability remediation, and compliance activities.
• Develop and maintain network diagrams, implementation plans, SOPs, configuration documentation, and technical reports.
• Partner with cybersecurity, systems administration, and mission teams to deliver secure and resilient network solutions.
• Support incident response, outage resolution, root cause analysis, change implementation, and network remediation efforts.
• Monitor network performance and recommend improvements to strengthen security, availability, reliability, and performance.
• Deliver technical leadership and guidance to network engineering and operations personnel.

Required qualifications

• U.S. citizenship required.
• Active TS/SCI clearance with SAP eligibility required.
• Bachelor’s degree in a related technical field, or additional relevant experience in lieu of a degree.
• Eight (8) or more years of experience in network engineering, network operations, or network security.
• Experience working in enterprise, defense, intelligence, federal government, or highly regulated environments.
• Strong hands-on experience with enterprise networking, including routing and switching; Layer 2 and Layer 3 troubleshooting; VLANs and subnetting; ACLs; network addressing and design; VPN technologies; network segmentation; resilient network architectures.
• Hands-on experience administering and troubleshooting enterprise firewalls.
• Experience with one or more firewall platforms, with Cisco Firepower and FMC preferred (Palo Alto Networks, Fortinet, Check Point, or other commercial or government enterprise firewall platforms also acceptable).
• Experience supporting firewall policy administration, rule management, NAT, VPNs, security zones, logging, monitoring, and troubleshooting.
• Experience supporting AAA, 802.1X, RMF, STIG, secure configuration, and network access control requirements.
• Cisco ISE experience preferred, particularly with authentication, authorization, accounting, policy enforcement, and network access control.
• Active DoD 8140/8570 IAT II certification, such as Security+ CE, CySA+, SSCP, or equivalent.
• Experience troubleshooting Cisco routers, switches, firewalls, and enterprise network infrastructure.
• Ability to work independently, lead technical efforts, and resolve complex network and security issues.
• Strong written and verbal communication skills.

Technologies you will work with

• Cisco Firepower, Firepower Management Center (FMC)
• Palo Alto Networks, Fortinet, Check Point
• Cisco ISE, 802.1X
• NAT, VPN technologies
• AAA (authentication, authorization, accounting)
• RMF, STIG
• Cisco routers, Cisco switches
• Security+ CE, CySA+, SSCP

Compensation and benefits

Salary range: USD 155,000 - 180,000 per year. Actual compensation will be determined based on several factors permitted by law.

• Healthcare benefits
• Paid leave
• Retirement plans
• Insurance programs
• Education and training assistance

Experience we value (not required)

• Experience supporting highly compartmented or special-access classified environments (helpful but not required).
• Cisco certifications, including CCNA, CCNP Enterprise, CCNP Security, or CCIE (helpful but not required).
• Experience with Palo Alto, Fortinet, Check Point, or other enterprise firewall technologies (helpful but not required).
• Experience with Cisco ISE, NAC, 802.1X, or related access control platforms (helpful but not required).
• Experience supporting network modernization, infrastructure upgrades, technology refresh, or network migration efforts (helpful but not required).
• Experience with incident response, change management, outage resolution, and root cause analysis in classified environments (helpful but not required).
• Familiarity with VMware or other virtualized environments (helpful but not required).
• Experience developing technical documentation, network diagrams, implementation plans, and SOPs (helpful but not required).

EEO: EEO Race/Sex/Disability Status/Veteran Status.