Principal Network Security Engineer (Firewalls & LAN/WAN) - TS/SCI w/Poly

GD Information Technology, Inc.; Herndon (VA); On-site; USD 145,000 - 196,000; Full time

Benefits offered by this job

401K with company match

Health and wellness packages

Internal mobility team supporting your

Professional growth including paid ed.

Paid vacation and holidays

Job summary

General Dynamics Information Technology, Inc. is seeking a seasoned Network Engineer to design and oversee complex IT infrastructure solutions. You will provide technical oversight, interpret requirements, and allocate tasks across components while aligning with security and best practices.

This role requires extensive experience with LAN/WAN, firewalls, and TS/SCI with Poly. You will collaborate with admins and developers, mentor junior engineers, and help plan capacity, monitoring, backups,

Qualifications

• Active TS/SCI with Poly clearance.
• Bachelor's or Technology degree in Engineering or related field, or equivalent.
• 14 years job-related experience.
• 10+ years of related Network Engineering experience.
• 12+ years configuring/maintaining Cisco ASA/NGFW.
• 10+ years configuring, designing, maintaining LAN/WAN devices.
• Proficient in routing concepts (EIGRP, OSPF, BGP, IP MPLS).

Responsibilities

• Define, maintain, and upgrade the overall security posture of the networks.
• Perform security audits and implement changes to improve security posture.
• Manage and allocate network installation and engineering tasks; configure LAN/WAN devices.
• Write build-to and as-built documentation and test plans for IT installations.
• Engage in system planning beyond the network for applications and systems.
• Provide expert analysis of voice, video, and data networks; upgrade OS and protocols.
• Mentor junior network engineers and support troubleshooting (Tier I–III).

Skills

Cisco ASA Firewall

LAN

Networks

Education

Bachelor's or Technology degree in Engineering or related field

Job description

Type of Requisition: Regular Clearance Level Must Currently Possess: Top Secret SCI + Polygraph Clearance Level Must Be Able to Obtain: Top Secret SCI + Polygraph Public Trust/Other Required: None Job Family: IT Infrastructure and Operations Job Qualifications: Skills: Cisco ASA Firewall, Local Area Network (LAN), Networks Certifications: None Experience: 10 + years of related experience US Citizenship Required: Yes

Job Description

The Network Engineer is responsible for designing technical solutions for complex problems. The candidate will provide technical oversight of a project solution, including requirement interpretation and allocation of requirements to technical components. The candidate will define processes to support the implementation of requirements. The candidate will be responsible for ensuring that the technical solutions leverage industry best practices, designing security and excellence while minimizing the total cost of ownership. Candidate should be able to define internal and external customer IT infrastructure architecture needs and then design solutions to meet those needs to include: capacity planning, systems configuration and tuning, monitoring backups, and installations of hardware and software. Candidates will be required to work independently with little supervision and should be flexible to work and support IT Operations needs as requested.

HOW A NETWORK ENGINEER WILL MAKE AN IMPACT

• Define, maintain, and upgrade the overall security posture of the networks
• Will perform security audits of events, overall health and implement changes to improve the overall programs security posture
• Manage and allocate network installation and engineering tasks, configure and maintain communications systems, familiarity with implementation of LAN and WAN equipment including firewalls, servers, workstations, routers, switches, hubs, storage devices, A/V equipment and equipment racks
• Ability to write and edit "build-to" and "as-built" documentation, as well as implementation and test plans for physical and logical installs of IT equipment
• Able to engage in technical system planning beyond the network, to include applications and systems that utilize the network being delivered
• Provides expert level analysis of voice, video, and/or data communications networks, including planning, designing, evaluating, selecting, and upgrading operating systems and protocol suites
• Able to plan network layouts and configures systems to user environments
• May provide technical support and troubleshooting to users. (Tier I, II, and III)

WHAT YOU'LL NEED TO SUCCEED

• The position requires an active TS/SCI with Poly clearance
• Bachelor's or Technology degree in Engineering or a related specialized area/field, OR equivalent
• 14 years job-related experience
• 10+ years of related Network Engineering experience
• 12 +years of experience configuring/maintaining Cisco ASA/Next Generation Firewall
• 10 + years of experience configuring, designing, maintaining, and troubleshooting LAN/WAN devices
• Thorough understanding of network routing concepts (EIGRP, OSPF, BGP, IP MPLS)
• Experience design, engineering, and deploying controlled interfaces (10 + years)
• Expertise/experience (more than 10) deploying Cisco, Palo Alto, or Juniper firewall
• Manager servers
• Experience allowing voice, video traffic across port-based firewall and NGFW
• Experience in engineering and deploying multi firewall solutions
• Experience design, engineering, and deploying firewall vendor transitioning plans
• Experience design, engineering, and deploying firewall in a multicast network environment
• Experience IPSec site-to-site VPN utilizing PKI (CA)
• Experiences Remote access VPN
• Basic understanding of QoS concepts
• Experience with network monitoring technologies
• Ability to take ambiguous requirements or problems and convert them into technical solutions
• Ability to partner with systems administrators, storage administrators, and application developers to solve complex problems
• Complex problem management research and issue resolution
• Ability to mentor junior network engineers
• Excellent organizational, coordination, interpersonal and team building skills
• Proven problem-solving skills in complex environments

DESIRED QUALIFICATIONS

• Experience configuring, designing, and troubleshooting QoS in LAN or WAN devices Juniper, Palo Alto, or Cisco Next Generation Firewalls
• Certifications and hands on experience
• Experience design, engineering, and deploying Muli-Factor Authentication solution
• Experience design, engineering, and deploying Zero-Trust solutions

GDIT IS YOUR PLACE

• 401K with company match
• Comprehensive health and wellness packages
• Internal mobility team dedicated to helping you own your career
• Professional growth opportunities including paid education and certifications
• Cutting-edge technology you can learn from
• Rest and recharge with paid vacation and holidays

#GDITCareers #cjpost #GDITPolyEvent #JET #VA_2026Alumni #GDITEnhanced2026 #MissionPoly2026

The likely salary range for this position is $144,500 - $195,500. This is not, however, a guarantee of compensation or salary. Rather, salary will be set based on experience, geographic location and possibly contractual requirements and could fall outside of this range.

Scheduled Weekly Hours: 40

Travel Required: None

Telecommuting Options: Onsite

Work Location: USA VA Herndon

Additional Work Locations: Total Rewards at GDIT

• Our benefits package for all US-based employees includes a variety of medical plan options, some with Health Savings Accounts, dental plan options, a vision plan, and a 401(k) plan offering the ability to contribute both pre and post-tax dollars up to the IRS annual limits and receive a company match.
• To encourage work/life balance, GDIT offers employees full flex work weeks where possible and a variety of paid time off plans, including vacation, sick and personal time, holidays, paid parental, military, bereavement and jury duty leave.
• To ensure our employees are able to protect their income, other offerings such as short and long-term disability benefits, life, accidental death and dismemberment, personal accident, critical illness and business travel and accident insurance are provided or available.
• We regularly review our Total Rewards package to ensure our offerings are competitive and reflect what our employees have told us they value most.

Identity Verification Process

• As part of the hiring process, we will ask you to complete an identity verification process that leverages advanced biometrics and artificial intelligence to ensure authenticity and protect against identity fraud.
• You are expected to be on camera during virtual interviews.
• We reserve the right to take your picture to verify your identity and prevent fraud.
• By proceeding, you authorize the collection, processing, and use of your biometric data for identity verification and security purposes.

About Our Work

We are GDIT. A global technology and professional services company that delivers technology solutions and mission services to every major agency across the U.S. government, defense and intelligence community. Our 26,000 experts extract the power of technology to create immediate value and deliver solutions at the edge of innovation. We operate across 50+ countries worldwide, offering leading mission-ready capabilities in AI, cloud, cyber and software development.

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