Sr. Tier III O&M Engineer

Leidos; South Dakota; On-site; USD 92,000 - 167,000; Full time

Job summary

Leidos is seeking a Sr. Tier III O&M engineer to support WAN/LAN networks, incident resolution, routing/firewall changes, and act as SME in WAN/LAN technologies. The role involves managing projects across OSPF/BGP/VRF/MPLS, troubleshooting, and performance optimization.

Expect extensive collaboration with configuration and implementation teams, after-hours support, and adherence to DoD IAT Level 2 and 8570 standards. TS/SCI with Poly is required.

Qualifications

• TS SCI with a Poly.
• 16 years of experience via work history and education.
• Must comply with DoD 8570 Information Assurance Technical (IAT) Level 2.
• Experience configuring and troubleshooting boundary protection technologies (Palo Alto, Cisco ASA, Forcepoint).
• Experience with Juniper and Cisco routers and switches.
• Experience with OSPF, BGP, VPNs, VRFs, MPLS.
• Knowledge of boundary protection best practices.
• Understanding of routing, switching, IP, NAT and security technologies.
• Ability to modify rulesets for new customer requirements.
• Ability to read and develop schematics and documentation.
• Working knowledge of Service Now or ITSM products.
• Superior verbal and written communication skills.
• MS Office (Word, Excel, PowerPoint, Visio).

Responsibilities

• Support operations and maintenance; administer LAN/WAN technologies (OSPF, BGP, VRFs, VLANs, VRRP, MPLS).
• Monitor performance of systems and networks.
• Configure and test hardware, networking software and OS software.
• Assess user requests for upgrades; advise on technical approaches.
• Perform long-term O&M and tier 3 troubleshooting.
• Prepare troubleshooting procedures for network restoration.
• Provide fault and performance management; respond to issues.
• Coordinate with configuration management and implementation teams.
• Analyze network characteristics and recommend changes to components.
• Optimize network topologies and site configurations.
• Coordinate requirements with users; document current configurations.
• Maintain systems, software, data bases, tools; ensure open systems compliance.

Skills

WAN/LAN engineering

Network troubleshooting

Routing protocols

Network security concepts

Documentation & reporting

Communication

Tools

Palo Alto

Cisco ASA

Forcepoint

Juniper routers

Cisco switches

VPNs

Job description

The Digital Modernization Sector at Leidos is seeking a Sr. Tier III operations and maintenance (O&M) engineer to support various WAN and LAN networks. Will provide incident resolution, routing changes, firewall changes; act as subject matter expert in WAN and LAN technologies; support intra- and inter- net and other data communications systems or segments of networked system.

Description of Job Duties/Responsibilities:

• Support operations and maintenance activities and administer networks including LAN and WAN technologies such as OSPF, BGP, VRF's, VLAN's, VRRP, MPLS.

• Monitor the performance of systems and networks

• Configure, and test hardware, networking software and operating system software

• Review user requests for upgrades or additions to the network to assess impact on network performance and provide advice and guidance on the most practical technical approach to meeting user requirements

• Perform long term O&M activities to include tier 3 troubleshooting and problem resolution

• Prepare troubleshooting procedures for restoring the network to optimal performance levels

• Provide fault management for the network and supports performance management functions

• Respond, isolate, and resolve network troubles

• Execute reporting functions and data input associated with network management

• Coordinate with configuration management and implementation teams

• Analyze network characteristics (e.g., traffic, connect time, transmission speeds, packet sizes, and throughput); recommend procurement, removals, and modifications to network components

• Optimize network topologies and site configurations.

• Coordinate requirements with users

• Assess and document current site network configuration and user requirements

• Maintain operating systems, communications software, data base packages, compilers, assemblers, and utility programs

• Apply software, hardware, and standards information technology skills in the analysis, specification, development, integration, and acquisition of open systems for Information Management (IM) applications

• Ensure these systems and applications are compliant with standards for open systems architectures, reference models, and profiles of standards - such as the IEEE Open Systems Environment (OSE) reference model - as they apply to the implementation and specification of IM solutions on the application platform, across the application program interface (API), and the external environment/software application

• May have up to 10% COMSEC responsibilities, as needed.

• Subject to be called in during afterhours for incident resolution.

Requirements

• TS SCI with a 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.

• Must comply with DoD 8570 Information Assurance Technical (IAT) Level 2.

• Experience in configuring and troubleshooting boundary protection technologies such as Palo Alto, Cisco ASA, and Forcepoint appliances

• Experience with configuring and troubleshooting Juniper and Cisco routers and switches.

• Experience with protocols such as OSPF, BGP, VPN's, VRF's, MPLS.

• Working knowledge of boundary protection best practices

• Understanding of routing, switching, Internet Protocol (IP) subnet, Network Address Translation (NAT) and security technologies

• Demonstrated ability to engineer and modify rulesets to allow connectivity for new customer requirements

• Demonstrated ability to read, understand, and develop schematic diagrams, technical manuals, and documentation such that the supported equipment and software can be maintained with minimal training

• Working knowledge of Service Now or similar IT Service Management (ITSM) products

• Superior verbal and written communication skills

• Intermediate-level knowledge of MS Office products Word, Excel, PowerPoint, and Visio

If you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo - because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 - and moving faster than anyone else dares.

Original Posting:

June 30, 2026

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 $92,300.00 - $166,850.00

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.