**Description** **The Digital Modernization Sector at Leidos** is seeking a **Sr. Core Network Engineer** to support our global enterprise networks. Our team is completely replacing a global enterprise network while providing design, engineering, and transition for a wide range of customer network requirements. This is a unique and rare opportunity to build and transition critical operations to a modern service provider network architecture. **BASIC QUALIFICATIONS:** + Demonstrated knowledge of Implementation of Perimeter and Internal Firewalls (both physical and virtual contexts) + Demonstrated advanced experience in managing standard baseline configuration across numerous firewalls + Demonstrated advanced experience in evaluating rules to ensure maximum security while minimizing redundancy in rules **PRIMARY RESPONSIBILITIES** + Train and mentor other team members. + Support mission-critical Continuity of Operations (COOP). + Provide expert advice and direction regarding the management and operation of all Palo Alto devices. + Follow up on all taskers and due outs. **Basic Requirements** + **TS/SCI with Poly** + Candidate must have 16 years of experience that can be a combination of work history and education. This equates to a Doctorate and 8 years, master’s and 10 years, bachelor’s and 12 years, associates and 14 years or HS diploma and 16 years. + Have hands-on Cisco / Forcepoint / Palo Alto Firewall experience in both engineering and Operations and maintenance roles. + Strong knowledge of Firewall concepts and best practices, including: Identifying misconfiguration, conflicting rules, security gaps, firewall security issues, optimize rule-sets, and enhance the overall security posture and performance of Firewalls. + Proficient understanding of the Cybersecurity Framework to identify, protect, detect, respond and recover within the Cyber Security Service Provider construct. + Motivated self-starter with strong written and verbal communication skills. + Experience working in a high op-tempo environment. **Preferred Qualifications** + Prior experienced with Enterprise and tactical networks, + Experience with DISA and DoD Networks. + Expertise in Vendor Equipment + Expertise in Networking / Firewall based Cybersecurity technologies (5+ years) + Skilled in building extended cyber security analytics. + Advanced Certifications such as SANS GIAC/GCIA/GCIH, CISSP or CASP. + Foster and encourage a collaborative environment to champion a cybersecurity culture Come break things (in a good way). Then build them smarter. We're the tech company everyone calls when things get weird. We don’t wear capes (they’re a safety hazard), but we do solve high-stakes problems with code, caffeine, and a healthy disregard for “how it’s always been done.” **Original Posting:** August 7, 2025 For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above. **Pay Range:** Pay Range $112,450.00 - $203,275.00 The Leidos pay range for this job level is a general guideline onlyand not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law. REQNUMBER: R-00164212 All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability or veteran status. Leidos will consider qualified applicants with criminal histories for employment in accordance with relevant Laws. Leidos is an equal opportunity employer/disability/vet.