Senior Network Engineer

The Defense sector at Leidos is seeking an experienced Senior Network Engineer to support a fast-paced Department of Defense (DoD) program supporting the Air Force Life Cycle Management Center (AFLCMC). The position supports the engineering, deployment, modernization, and sustainment of network infrastructure across multiple customer locations. The Senior Network Engineer will serve as a senior technical contributor responsible for translating mission and technical requirements into secure, resilient, and supportable network solutions. They will participate throughout the network engineering lifecycle, including requirements analysis, architecture and design, hardware/software selection, procurement support, staging, implementation, testing, troubleshooting, documentation, and operational transition. The successful candidate will have hands-on experience with enterprise routing, switching, firewalls, WAN technologies, secure communications, and network management in DoD or similarly regulated environments. This position does require the ability to work 100% on-site at our location in Lorton, VA.  Primary responsibilities: Develop detailed network architectures and engineering designs aligned with DoD, Air Force, cybersecurity, availability, and mission requirements. Translate operational and technical requirements into network designs, implementation plans, equipment specifications, Bills of Materials (BOMs), and technical documentation. Design, configure, deploy, and troubleshoot enterprise network infrastructure, including routers, Layer 2/Layer 3 switches, firewalls, VPN gateways, and associated network services. Engineer LAN and WAN solutions incorporating technologies such as Ethernet, VLANs, trunking, Spanning Tree Protocol (STP), link aggregation, QoS, access control lists (ACLs), and redundant/high-availability architectures. Configure and troubleshoot routing technologies and protocols such as BGP, OSPF, and static routing in enterprise and multi-site environments. Design and support secure WAN connectivity using technologies such as IPsec, site-to-site VPNs, MPLS, and other DoD-approved transport solutions. Support implementation and troubleshooting of network security technologies, including firewalls, network segmentation, access controls, secure management interfaces, and encrypted communications. Perform packet-level and protocol analysis to identify network performance, connectivity, routing, security, and interoperability issues. Utilize network monitoring and troubleshooting technologies such as SNMPv3, Syslog, ICMP, NetFlow, packet capture, and network management platforms to identify and resolve operational issues. Develop test plans and conduct verification and validation of network solutions to confirm functionality, performance, resiliency, interoperability, and cybersecurity compliance. Conduct pre-deployment staging, configuration validation, and implementation readiness activities prior to installation at customer locations. Troubleshoot complex network issues during deployment, testing, and operational sustainment and perform root-cause analysis when required. Develop and maintain network documentation, including logical and physical network diagrams, IP address plans, configuration baselines, interface documentation, rack elevations, cable diagrams, and as-built documentation. Maintain configuration control and document network changes in accordance with established change and configuration management processes. Support DoD cybersecurity requirements, including applicable Security Technical Implementation Guides (STIGs), security controls, vulnerability remediation, and Risk Management Framework (RMF) activities. Collaborate with cybersecurity engineers to ensure network infrastructure meets applicable DoD security and Zero Trust requirements. Provide technical leadership and guidance to junior engineers and field personnel during network installation, integration, troubleshooting, and operational turnover. Support technical reviews, engineering meetings, site surveys, deployment planning, and customer technical discussions. Provide technical input to procurement activities and evaluate network hardware/software against technical, security, interoperability, lifecycle, and mission requirements. Maintain awareness of emerging network, cybersecurity, cloud, automation, and DoD enterprise networking technologies and recommend improvements where appropriate. Basic Qualifications: US Citizen with an active Top Secret clearance with the ability to obtain and main a SCI prior to your start date. Bachelor's degree with 8+ years of experience or a Master’s degree with 6+ years of experience. Additional experience may be considered in lieu of a degree. Demonstrated experience designing, implementing, configuring, and troubleshooting enterprise network infrastructure. Strong understanding of the OSI and TCP/IP models and network protocols associated with Layers 1–4. Hands-on experience configuring enterprise routers and switches. Experience implementing and troubleshooting LAN technologies, including VLANs, 802.1Q trunking, STP/RSTP, link aggregation, and Layer 3 switching. Experience with IP addressing, subnetting, route selection, access control lists, and network segmentation. Working knowledge of dynamic routing protocols such as BGP and OSPF. Experience designing, deploying, or supporting WAN connectivity across geographically separated locations. Experience implementing or supporting IPsec/site-to-site VPN technologies. Experience using network monitoring and troubleshooting technologies such as ICMP, SNMPv3, Syslog, packet captures, and network management platforms. Experience troubleshooting complex network connectivity, routing, performance, and configuration issues. Ability to develop and maintain detailed technical documentation and network diagrams. Understanding of network security principles, secure management pra