Network Security Engineer

General information

Requisition #

R69874

Locations

USA-VA-Chantilly

Posting Date

08/12/2026

Security Clearance Required

TS/SCI

Remote Type

Onsite

Time Type

Full time

Description & Requirements

Shape the future of defense with MANTECH! Join a team dedicated to safeguarding our nation through advanced tech and innovative solutions. Since 1968, we've been a trusted partner to the Department of Defense, delivering cutting-edge projects that make a real impact. Dive into exciting opportunities in Cybersecurity, IT, Data Analytics and more. Propel your career forward and be part of something extraordinary. Your journey starts now-protect and innovate with MANTECH!

MANTECH seeks a motivated, career and customer-oriented Network Security Engineer to join our team in Chantilly, VA. This is an onsite position.

Responsibilities include but are not limited to:

• Perform Tier II and Tier III network security engineering support, while assisting in designing advanced WAN, LAN, and data center solutions.

• Monitor and configure networks utilizing SolarWinds, Cisco Firepower FMC, and Cisco ISE to analyze complex network requirements and ensure complete, functioning infrastructure

• Create, maintain, and interpret highly detailed technical network security diagrams, routing topology schemas, and robust hardware configuration baselines

• Coordinate across large internal teams, stakeholders, and Sponsor authorities to drive infrastructure agendas and successfully navigate systems engineering processes

• Participate in all phases of the ITIL Service Lifecycle, including submitting Change Requests and maintaining security event monitoring policies

• Evaluate current network security architectures, inventory complex routing pathways, and recommend process improvements to optimize performance and throughput

• Deliver end-to-end functional analysis, requirements specification, cost estimation, and engineering package releases for customer production IT environments

Minimum Qualifications:

• High School Diploma or GED with 7+ years of progressively responsible experience in Network Security Engineering, Network Analysis, or a related technical discipline

• Cisco Certified Network Associate (CCNA) certification, or equivalent routing/switching technical certification, ex., Juniper Networks Certified Associate - Junos (JNCIA-Junos)

• DoD 8570 IAT Level II Certification, e.g., Security+

• DoD 8570.1 / DoD 8140.01 (IAT III Level) certification required within 6 months of hire, e.g., SecurityX

Preferred Qualifications:

• Bachelors degree in an engineering discipline

• Experience using and administering SolarWinds alongside deep knowledge of Microsoft Windows Systems, HP SANs, and VMware products

• Advanced experience managing VPNs, GRE tunnels, routing protocols (BGP E/I, OSPF), VLANs, VRFs, and configuring KGs

• Strong familiarity with Cisco ACI, data center fabric best practices, Ansible, and Desired State Configuration (DSC)

• Strong familiarity with Cisco Secure Firewall ( Firepower FMC)

• Practical knowledge of BICSI standards, terminating fiber and Cat 5 cabling, as well as familiarity with NSTISSAM TEMPEST/2-95 and CNSSAM TEMPEST/01-13 guidelines

Clearance Requirements:

• Must have a current and active TS/SCI clearance

Physical Requirements:

• The person in this position must be able to remain in a stationary position 50% of the time. Occasionally move about inside the office to access file cabinets, office machinery, or to communicate with co-workers, management, and customers, via email, phone, and or virtual communication, which may involve delivering presentations.

The projected compensation range for this position is $104,200.00-$172,900.00. There are differentiating factors that can impact a final salary/hourly rate, including, but not limited to, Contract Wage Determination, relevant work experience, skills and competencies that align to the specified role, geographic location (For Remote Opportunities), education and certifications as well as Federal Government Contract Labor categories. In addition, MANTECH invests in its employees beyond just compensation. MANTECH's benefits offerings include, dependent upon position, Health Insurance, Life Insurance, Paid Time Off, Holiday Pay, short-term and long-term Disability, Retirement and Savings, Learning and Development opportunities, wellness programs as well as other optional benefit elections.

MANTECH considers all qualified applicants for employment without regard to disability or veteran status or any other status protected under any federal, state, or local law or regulation.

If you need a reasonable accommodation to apply for a position with MANTECH, please email us at careers@mantech.com and provide your name and contact information.