Network Engineer - Senior (Top Secret Clearance Required)

i3, LLC; Chantilly (VA); On-site; USD 120,000 - 160,000; Full time

Job summary

i3, LLC is seeking a Senior Network Engineer to lead design, implementation, and optimization of resilient network infrastructures supporting mission-critical operations. The role requires strategic and technical leadership in modernization, security architecture, and performance optimization across complex, multi-enclave environments.

The candidate will oversee secure communications and network security standards, driving modernization aligned with zero-trust principles while collaborating with

Qualifications

• Extensive experience designing and supporting enterprise networks.
• Expertise in routing, switching, firewalls, VPNs, and network security.
• Experience implementing zero-trust architectures and secure communications in multi-enclave environments.

Responsibilities

• Design and implement enterprise network architectures for secure, mission-critical operations.
• Lead zero-trust network design initiatives and cross-enclave interoperability solutions.
• Optimize network performance, reliability, and security across complex, multi-enclave environments.
• Establish and enforce network security architecture standards and governance processes.
• Drive modernization efforts aligned with enterprise strategy and zero-trust principles.
• Ensure secure communications across classified and regulated environments.
• Provide technical leadership for network infrastructure planning and implementation.
• Partner with security, architecture, and operations teams to maintain resilient networks.

Skills

Cisco Switching

Cisco Routing

Cisco Firewalling

Site-to-Site VPNs

Arista Switching

VPN Tunnels

VMware ESXi

Proxmox

Nutanix Prism

NFS/Samba

QNAP Synology

Nessus

Splunk

Linux

IPA/FreeIPA

LDAP

Keycloak

Docker

Kubernetes

GitLab

Nginx

Jira

Confluence

Jupyter

Education

Bachelor's degree

Tools

VMware ESXi

Proxmox

Nutanix Prism

vCenter

VSAN

VxRail

Ceph

NFS

Samba

SSH

SFTP

Nessus

Splunk

Nginx

Confluence

Jira

Docker

Kubernetes

GitLab

Jupyter

Job description

Network Engineer - Senior

"Bachelors required Minimum 8 years experience This role leads the design, implementation, and optimization of resilient, secure network infrastructures supporting mission-critical operations. The SME provides strategic and technical leadership in network modernization, security architecture, and performance optimization while ensuring secure and reliable communications across complex, multi-enclave environments."

Unique Skills / Technical Requirements

• Networking o Cisco: Switching, Routing, Firewalling, and Site-to-site functionality (such as IPSEC, DMVPN, and SD-WAN) o Arista: Switching o Tunneling & VPNs: GRE, IPSEC, SSH, SSL, OpenVPN, Wireguard, and specialized multi-tiered applications o Virtual Distributed Switching: VMWare, Proxmox, and Nutanix o Solutions & Hardware: Client-Server VPNs, Site-to-site VPNs, and ad-hoc vendors or equipment
• Virtualization / Hyper-Converged Infrastructure o VMWare / Broadcom: ESXi (vSphere), vCenter, VSAN, VxRail, Cluster management, and Licensing o Proxmox: Host and cluster configuration/management, Networking, and Ceph configuration/management o Nutanix: Host and cluster configuration, management with Prism Central, and NDFS configuration/management
• Large Data Storage Technologies o Hardware/Vendors: QNAP, Synology, TrueNAS, and NetApp o File Transport Protocols: Samba, SSH, SFTP, and NFS
• Monitoring & Security o Monitoring: Network-based and Host-based collection and monitoring o Alerting & Scanning: Internal and external alerting (including SMTP configuration), and Active vulnerability scanning (such as Nessus) o SIEM: Splunk familiarity
• System Administration o Operating Systems: Linux (e.g., Rocky, RedHat, Amazon, Ubuntu), Windows, and Mac OS o Identity & Access Management: IPA / FreeIPA, LDAP / OpenLDAP, Keycloak, and Linux-based SSSD host-based access control (HBAC)
• Applications o Splunk, Nginx, Confluence, Jira, Docker, Kubernetes, GitLab, and Jupyter

Advanced Networking: Multi-tiered Key Responsibilities

• Design and implement enterprise network architectures that support secure, mission-critical operations.
• Lead zero-trust network design initiatives and cross-enclave interoperability solutions.
• Optimize network performance, reliability, and security across complex, multi-enclave environments.
• Establish and enforce network security architecture standards and governance processes.
• Drive network modernization efforts aligned with enterprise strategy and zero-trust principles.
• Ensure secure communications and connectivity across classified and highly regulated environments.
• Provide technical leadership for network infrastructure planning and implementation.
• Partner with security, architecture, and operations teams to maintain resilient network systems.

Required Skills

Extensive experience designing and supporting enterprise network environments. Strong expertise in routing, switching, firewalls, VPNs, network security, and access control technologies. Experience implementing zero-trust architectures and secure communications solutions. Advanced troubleshooting and network performance analysis skills. Experience supporting mission-critical, highly secure, or regulated environments. Strong leadership, communication, and technical documentation skills.

Preferred Skills

Master's degree in Information Technology, Network Engineering, Cybersecurity, or related field. Experience supporting federal, defense, intelligence, or classified network environments. Expertise with multi-enclave or cross-domain network architectures. Experience with cloud networking, software-defined networking (SDN), and hybrid cloud environments. Knowledge of security accreditation processes and compliance frameworks. Relevant certifications such as CCNP, CCIE, CISSP, JNCIP, JNCIE, AWS Advanced Networking, or equivalent.