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 infrastructureCreate, maintain, and interpret highly detailed technical network security diagrams, routing topology schemas, and robust hardware configuration baselinesCoordinate across large internal teams, stakeholders, and Sponsor authorities to drive infrastructure agendas and successfully navigate systems engineering processesParticipate in all phases of the ITIL Service Lifecycle, including submitting Change Requests and maintaining security event monitoring policiesEvaluate current network security architectures, inventory complex routing pathways, and recommend process improvements to optimize performance and throughputDeliver end-to-end functional analysis, requirements specification, cost estimation, and engineering package releases for customer production IT environmentsMinimum Qualifications:High School Diploma or GED with 7+ years of progressively responsible experience in Network Security Engineering, Network Analysis, or a related technical disciplineCisco 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 (IAT III Level) certification required within 6 months of hire, e.g., SecurityXPreferred Qualifications:Bachelors degree in an engineering disciplineExperience using and administering SolarWinds alongside deep knowledge of Microsoft Windows Systems, HP SANs, and VMware productsAdvanced experience managing VPNs, GRE tunnels, routing protocols (BGP E/I, OSPF), VLANs, VRFs, and configuring KGsStrong 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 guidelinesClearance Requirements:Must have a current and active TS/SCI clearancePhysical 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.