Senior Firewall Engineer

Join the Leidos Homeland Sector and contribute to a high-impact international program delivering secure, next-generation private cloud capabilities within a NATO-secured environment. This senior-level role offers the opportunity to apply deep technical expertise to the design, integration, and hands-on implementation of enterprise backup, recovery, and cyber resilience solutions supporting a Software-Defined Data Center (SDDC). You will help deliver secure, resilient, and automated data protection capabilities across Enterprise Core Services (ECS), Client Provisioning Services (CPS), Infrastructure as a Service (IaaS), and Service Management Control (SMC). Working closely with infrastructure, virtualization, cybersecurity, and DevOps teams, you will support the full delivery lifecycle—from solution design and integration through site deployment, testing, disaster recovery validation, and customer acceptance. This position offers an exciting opportunity to work directly with international customers and technical partners, with approximately 25% travel to The Hague, Netherlands, and other NATO locations as needed to support solution integration, implementation, testing, and customer acceptance. It is an ideal opportunity for a senior engineering leader interested in advancing mission-critical cloud capabilities while gaining valuable international program experience. Responsibilities: Lead the design, automation, integration, and hands-on implementation of enterprise firewall and network security solutions supporting private cloud SDDC modernization initiatives. Design and implement secure firewall architectures supporting Enterprise Core Services (ECS), Client Provisioning Services (CPS), Infrastructure as a Service (IaaS), DevOps platforms, and Service Management Control (SMC). Develop and implement network segmentation strategies using Palo Alto Networks, VMware NSX Distributed Firewall, Cisco security technologies, or equivalent enterprise security platforms. Design and integrate enterprise security controls, micro-segmentation, identity-based access controls, and defence-in-depth principles supporting NATO Operational Network (ON) security requirements. Collaborate with cybersecurity, networking, virtualization, and infrastructure engineering teams to integrate enterprise security services into platform solutions. Develop security automation using Infrastructure as Code (IaC), Ansible, Terraform, APIs, or similar automation technologies to standardize firewall configuration and policy management. Integrate Commercial Off-The-Shelf (COTS) security solutions into secure enterprise environments while ensuring compliance with NATO security policies, programme requirements, and customer security architecture. Develop and maintain firewall architectures, security designs, implementation plans, configuration standards, and engineering documentation. Participate in Agile development activities including sprint planning, technical reviews, security architecture reviews, and cross-functional engineering collaboration. Mentor engineers and provide technical guidance on enterprise firewall engineering, network security, defence-in-depth principles, and secure-by-design engineering practices. Travel to NATO sites to install, configure, integrate, validate, and troubleshoot enterprise firewall and network security solutions while supporting deployment, commissioning, security testing, and customer acceptance activities. Support cybersecurity planning, infrastructure modernization initiatives, security accreditation activities, and proposal development. Required Experience, Skills, and Education: Bachelor's degree in Computer Science, Information Technology, Engineering, Cybersecurity, or related discipline with 8–12 years of relevant experience, or Master's degree with 6–10 years of relevant experience. Active NATO Secret clearance (or higher). Demonstrated experience designing and implementing enterprise firewall and network security solutions. Strong experience with Palo Alto Networks firewalls, including policy management, threat prevention, and security architecture. Experience with VMware NSX Distributed Firewall, Cisco security technologies, or equivalent enterprise network security platforms. Strong understanding of enterprise security architecture, defence-in-depth principles, network segmentation, identity and access management, and secure systems design. Experience integrating firewall solutions into VMware private cloud, SDN, or hybrid cloud environments. Extensive experience with implementing security automation using Infrastructure as Code (IaC), Ansible, Terraform, Python, or similar technologies. Strong understanding of enterprise networking, routing, switching, VPNs, PKI, and enterprise cybersecurity practices. Experience operating within Agile, SAFe, or DevSecOps delivery frameworks. Strong leadership, communication, stakeholder engagement, and technical collaboration skills. Experience supporting defence, government, or highly regulated development environments. Preferred Experience, Skills, and Education: Palo Alto Networks Certified Network Security Engineer (PCNSE) or equivalent certification. VMware NSX certification or equivalent SDN security certification. Experience supporting NATO environments and compliance frameworks. Experience with F5 Application Delivery Controllers (ADC) and Web Application Firewalls (WAF). Experience with Security Information and Event Management (SIEM), Security Orchestration, Automation and Response (SOAR), or enterprise security monitoring platforms. Familiarity with Python, REST APIs, and security automation technologies. Experience supporting large-scale infrastructure modernization and enterprise platform engineering initiatives. If you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares. Original Posting: August 10, 2026 For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above. Pay Range: Pay Range $107,900.00 - $195,050.00 The Leidos pay range for this job level is a general guideline only and not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.