[Remote] Senior Network Security Engineer

Note: The job is a remote job and is open to candidates in USA. MANTECH is hiring a Senior Network Security Engineer to lead network modernization and transition legacy architectures to a secure, cloud-integrated TIC 3.0 framework. The role focuses on secure network boundaries, firewall and switching engineering, automation, observability, vulnerability remediation, and high-availability operations.

Responsibilities

• Perimeter Architecture & TIC 3.0 Transition: Design, configure, and maintain our geographically distributed network boundaries. Architect and engineer secure site-to-site IPsec VPN tunnels and related components to modernize our boundary from TIC 2.0 colocation centers to cloud-integrated TIC 3.0 secure overlays
• Multi-Vendor Firewall & Switching Engineering: Perform expert-level administration, configuration, and troubleshooting of our enterprise firewall and switching planes. This includes configuring and managing products that may include, Palo Alto Networks Next-Generation Firewalls, Fortinet FortiGate appliances, as well as Juniper and Brocade switches
• GitOps & Automation Integration: Maintain and enforce network configuration baselines using Infrastructure as Code (IaC) techniques. Collaborate with our tools development team to write and execute Ansible playbooks and GitLab CI/CD pipelines to automate VLAN assignments, port configuration, and dynamic DNS sinkhole blocks
• Network Observability & Traffic Analysis: Utilize packet brokers to capture and route packet streams. Operate tools and technologies to monitor internal network flows and detect anomalous lateral movement. Integrate out-of-band network probing utilities to continuously track perimeter performance
• Technical Documentation & Configuration Management: Develop and maintain up-to-date, accurate documentation of network cabling, IP Addresses, MAC addresses, and VLAN assignments for critical systems. Utilize tools to generate dynamic network topology maps, execute runbooks, and automate configuration drift audits
• Vulnerability Remediation & Compliance: Collaborate closely with the ISSO and Vulnerability Assessment Teams. Run network vulnerability scans, analyze results, apply Security Technical Implementation Guides (STIGs/CIS), and execute directed patching or configuration changes
• COOP & High-Availability Operations: Configure and maintain High-Availability (HA) firewalls, actively diagnosing active-active split-brain states or persistent ARP resolution bugs. Participate in a 24/7 on-call rotation with a strict one-hour response window for service-impacting network events

Skills

• The candidate must possess a strong, proactive problem-solving mindset and be comfortable working in a high-tempo, availability-first environment
• Bachelor's degree in Computer Science, Computer Systems Engineering, Cybersecurity, or a related field with 5+ years of direct Systems or Network Engineering experience or Associate's degree in a related field with 8+ years of relevant experience or 11+ years of relevant experience with no degree
• Minimum of 3 years of hands-on administration of Palo Alto Networks firewalls (PAN-OS) and Juniper core switching infrastructure (Junos OS) in an enterprise environment
• In-depth technical mastery of BGP routing (including BGP Anycast configurations and route-withdrawal failover scripts), OSPF, and IPsec VPN tunneling
• Proven working knowledge of federal security compliance standards, including FISMA, the NIST Risk Management Framework (RMF) SP 800-53 Rev. 5, and CISA Zero Trust guidelines
• Must be a US citizen with a current/active Secret clearance
• Possession of one or more of the following professional, role-based security certifications is highly desired to align with Department of Commerce (DOC) CAT Standards:
• ISC2 CISSP (Certified Information Systems Security Professional) or ISSAP (Information Systems Security Architecture Professional)
• Cisco CCIE Security, CCDE, or CCAr
• ISC2 CCSP (Certified Cloud Security Professional)
• Active CCNA or Advanced Palo or Juniper-equivalent certifications
• Experience scripting in Python or Bash and building custom playbooks in Ansible to manage network configurations
• Experience setting up secure transit gateways and VPC routes within Amazon Web Services (AWS) or Microsoft Azure environments

Benefits

• Health Insurance, dependent upon position
• Life Insurance, dependent upon position
• Paid Time Off, dependent upon position
• Holiday Pay, dependent upon position
• Short-term and long-term Disability, dependent upon position
• Retirement and Savings, dependent upon position
• Learning and Development opportunities, dependent upon position
• Wellness programs, dependent upon position
• Other optional benefit elections, dependent upon position

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