Sr. Network Engineer - Herndon, VA- TS/SCI with Poly

Transform technology into opportunity as a Sr. Network Engineer with GDIT. A career in enterprise IT means connecting and enhancing the systems that matter most. At GDIT you’ll be at the forefront of innovation and play a meaningful part in improving how agencies operate.

At GDIT, people are our differentiator. As a Sr. Network Engineer you will help ensure today is safe and tomorrow is smarter. Our work depends on Network Engineer Senior joining our team to support our client’s mission.

 GDIT is seeking an experienced and mission-driven Network Engineer to support the design, implementation, and sustainment of Cross-Domain Solutions (CDS) in a secure, multi-domain environment for a high-impact program within the U.S. government.

Key Responsibilities:

• Design and manage secure, policy-enforced networks supporting CDS architectures across multiple security domains (e.g., TS/SCI, Secret, Unclassified).
• Collaborate with security engineers, CDS developers, and mission stakeholders to architect solutions that meet mission and policy requirements.
• Deploy, configure, and maintain network devices (routers, switches, firewalls, TAPs) and virtual networking within air-gapped and compartmented environments.
• Support the integration of NSA-approved CDS technologies into enterprise and tactical environments.
• Troubleshoot and resolve complex network and cross-domain data flow issues in a secure, mission-critical setting.
• Ensure all networking components are configured per ICD 503, CNSS policies, and relevant Cross Domain Risk Management (CDRM) guidelines.
• Participate in system hardening, vulnerability assessments, and Authority to Operate (ATO) efforts in partnership with ISSOs and Information Systems Security Engineers (ISSEs).
• Maintain system documentation, including CONOPS, security plans, interface control documents (ICDs), and network diagrams for accreditation and operational use.
• Support lab testing, operational evaluations, and live deployments across IC or partner agency environments.

Required Experience:

• Active TS/SCI with CI (polygraph required at start or willingness to sit).
• Bachelor’s degree in Network Engineering, Information Systems, or related technical field, or equivalent experience (or equivalent experience).
• 8+ years of experience supporting secure network infrastructure within the Intelligence Community or DoD.
• Strong knowledge of Layer 2/3 networking, VLANs, routing protocols (BGP, OSPF), NAT, ACLs, and network segmentation.
• Proficient with Cisco, Juniper, Palo Alto, or similar platforms.
• Direct experience supporting or integrating one or more NSA-evaluated CDS solutions.
• Familiarity with ICD 503, NIST 800-53, CNSSI 1253, and related A&A processes.
• Experience working in air-gapped, high-side/low-side data transfer environments.

Preferred Skills:

• Experience with specific CDS platforms
• Understanding of Zero Trust principles and segmentation in classified environments.
• Familiarity with DevSecOps, software-defined networking (SDN), or IC cloud environments (C2S, SC2S).
• Industry certifications such as CCNA/CCNP, Security+, CISSP, or CEH.
• Experience supporting lab environments and integration test events.
• Knowledge of virtualization platforms (VMware, KVM) and secure system administration.

Knowledge of SAFE Agile principles. 

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.