Network Defense Design Engineer Senior

Leidos is looking to hire a Network Defense Design Engineer Senior in Quantico, VA to join our SMIT program. The qualified candidate will assist the Government Lead with daily network defense engineering activities, including the design, implementation, integration, administration, maintenance, and optimization of enterprise cybersecurity systems and infrastructure.  The Network Defense Design Engineer Senior will also engineer and integrate cybersecurity architectures, security controls, and defensive mechanisms into enterprise information systems to meet Department of Defense (DoD), Navy, and Marine Corps security requirements.

The Leidos team delivers the core backbone of the Service, Management, Integration and Transport (SMIT) program, including cybersecurity services, network operations, service desk, and data transport. Leidos will support network modernization efforts to provide Sailors, Marines, and the civilian workforce with the tools they need to be more efficient at increasing naval capabilities and further empowering the Navy Marine Corps team to compete and win.

Primary responsibilities include, but are not limited to:

- Design, develop, and implement enterprise network defense solutions to ensure availability, integrity, authentication, confidentiality, and non-repudiation of information systems and network resources.
- Design, implement, and maintain enterprise Security Information and Event Management (SIEM) solutions supporting centralized logging, security event correlation, incident detection, investigation, and reporting.
- Design and integrate enterprise logging, network forensics, intrusion detection, and intrusion prevention capabilities to strengthen cybersecurity monitoring and incident response operations.
- Design and implement the Enterprise Services portion of the Cybersecurity Sensor Grid, integrating intrusion, incident, and audit data from multiple security technologies, including content monitoring, content filtering, Host-Based Security System (HBSS), and network security sensors.
- Engineer and integrate hardware-based security sensors into Navy and Marine Corps enterprise architectures to support current and emerging Computer Network Defense (CND) technologies.
- Design and implement security monitoring solutions supporting packet capture, deep packet inspection, customized intrusion detection signatures, and advanced network traffic analysis.
- Design, configure, and integrate CND mechanisms, including anti-spam technologies, Network Access Control (NAC), HBSS, intrusion prevention systems, and host-based device control modules across enterprise environments.
- Engineer and integrate intrusion prevention and security event monitoring solutions utilizing McAfee Intrusion Prevention System (IPS), McAfee SIEM, and other Government-approved cybersecurity technologies.
- Design, implement, and maintain Network Access Control (NAC) solutions to enforce device authentication, endpoint compliance, access authorization, and enterprise network security policies.
- Integrate vulnerability assessment and network scanning technologies, including Assured Compliance Assessment System (ACAS), to identify vulnerabilities, assess security compliance, and support remediation activities.
- Design, plan, and implement enterprise cybersecurity measures in accordance with established Cyber Readiness Conditions (CYBERCON) and Government-directed defensive requirements.
- Develop, implement, and maintain cybersecurity policies, technical security plans, procedures, and configuration standards to ensure enterprise systems comply with Government security requirements.
- Assist with the development and integration of Identity and Access Management (IAM) requirements, including role-based access controls, privileged account management, and enterprise authentication services.
- Design and integrate Public Key Infrastructure (PKI), certificate-based authentication, and two-factor authentication solutions for Active Directory (AD) domain accounts, network devices, and enterprise applications to reduce reliance on password-based authentication.
- Design, configure, and integrate Microsoft Active Directory (AD) and Lightweight Directory Access Protocol (LDAP) services to support secure authentication and authorization for enterprise network devices, appliances, and applications.
- Monitor, troubleshoot, and optimize directory services replication, authentication services, and supporting infrastructure to maintain system availability and performance.
- Oversee Rights Management Services for administrators, users, and groups to ensure appropriate access permissions and compliance with Government security policies.
- Design and integrate cybersecurity solutions supporting application networking ports, protocols, Information Assurance (IA) requirements, routing, and Local Area Network (LAN) connectivity.
- Develop, maintain, and execute Continuity of Operations (COOP) and Disaster Recovery (DR) plans, including system backups, restoration procedures, and operational recovery requirements.
- Support information system security assessments, certification and authorization activities, and compliance validation to ensure enterprise systems meet applicable cybersecurity standards.
- Develop and manage Plans of Action and Milestones (POA&Ms) to document security deficiencies, track corrective actions, and support system compliance and risk management objectives.
- Perform cybersecurity architecture assessments, configuration reviews, integration testing, verification, and validation to ensure network defense solutions meet technical, operational, and security requirements.
- Ensure network defense designs and implementations support Navy, Marine Corps, Defense Information Systems Agency (DISA), and Joint interoperability requirements.
- Plan, coordinate, and execute cybersecurity system upgrades, migrations, integrations, and infrastructure modernization activities while minimizing operational disruptions.
- Develop and maintain technical documentation, security architecture diagrams, implementation plans, configuration baselines, standard operating procedures (SOPs), and engineering recommendations.
- Provide senior-level technical expertise and recommendations to Government stakeholders and engineering teams regarding network defense architecture, security integration, vulnerability management, and enterprise cybersecurity improvements.

Basic Qualifications:

- Bachelor’s degree in computer science, Management Information Systems (MIS), Business, Cybersecurity, Information Technology, or a related field.
- Minimum of 10 years of relevant experience in network defense engineering, cybersecurity architecture, information assurance, security systems integration, or enterprise cybersecurity operations.
- US Citizen with an active DoD Secret security clearance.
- Must possess an Information Assurance Technician (IAT) Level III certification in accordance with applicable DoD requirements.
- Must possess an Information Technology Infrastructure Library (ITIL) Version 3 Foundation certification.
- Extensive experience designing, implementing, integrating, and maintaining enterprise network defense architectures and cybersecurity technologies.
- Hands-on experience with Security Information and Event Management (SIEM) solutions, including McAfee SIEM or comparable enterprise security monitoring platforms.
- Experience with intrusion detection and prevention technologies, including McAfee IPS, host-based security solutions, and network security sensors.
- Experience designing and integrating Network Access Control (NAC) solutions, endpoint security technologies, and enterprise access enforcement mechanisms.
- Experience utilizing Assured Compliance Assessment System (ACAS) or comparable vulnerability assessment and network scanning technologies.
- Ability to develop technical documentation, evaluate network defense architecture alternatives, and communicate engineering recommendations to technical teams and Government stakeholders.

Preferred Qualifications:

- Advanced cybersecurity certifications such as Certified Information Systems Security Professional (CISSP), Certified Information Security Manager (CISM), or equivalent.
- Experience supporting the Marine Corps Enterprise Network (MCEN), Navy Marine Corps Intranet (NMCI), or comparable Department of Defense enterprise networks.
- Experience designing and integrating enterprise security monitoring architectures, including centralized logging, SIEM, network sensors, and security event correlation platforms.
- Experience with McAfee IPS, McAfee SIEM, HBSS, and other DoD-approved endpoint and network defense technologies.
- Experience integrating Network Access Control (NAC), vulnerability assessment, and endpoint compliance solutions into large-scale enterprise networks.
- Familiarity with DoD cybersecurity policies, Risk Management Framework (RMF), Security Technical Implementation Guides (STIGs), and network security compliance requirements.
- Experience with Navy/Marine Corps, DISA, and Joint network interoperability requirements.
- Experience supporting cybersecurity readiness activities, enterprise defensive measures, and Government-directed security posture changes.
- Experience designing and implementing PKI, certificate-based authentication, Active Directory security, and enterprise Identity and Access Management (IAM) solutions.
- Experience supporting network defense modernization, enterprise cybersecurity migrations, and large-scale security infrastructure integration projects.
- Experience developing security architecture documentation, engineering implementation plans, technical assessments, and cybersecurity remediation strategies.
- Strong understanding of Computer Network Defense (CND) principles, including intrusion detection, security event correlation, packet inspection, network monitoring, and incident response.
- Experience integrating Host-Based Security System (HBSS), device control modules, content filtering, and other enterprise cybersecurity technologies.
- Experience with Microsoft Active Directory (AD), Lightweight Directory Access Protocol (LDAP), directory services replication, and enterprise identity management.
- Experience implementing Public Key Infrastructure (PKI), certificate-based authentication, and multifactor authentication solutions within enterprise environments.
- Strong understanding of network protocols, routing, LAN technologies, application ports, and network security controls.
- Experience developing and implementing Continuity of Operations (COOP), Disaster Recovery (DR), backup, and system recovery solutions.
- Experience supporting DoD cybersecurity compliance activities, including security assessments, vulnerability remediation, and Plans of Action and Milestones (POA&Ms).

NGEN

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.

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## Original Posting:
November 13, 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.