3rd Line Network Engineer
Confirmed on the employer's own hiring board on Oct 18, 2026. First seen by Alion on Aug 12, 2026. Leidos scores B on the Alion truth index.
3rd Line Network Engineer
Location: Farnborough
Clearance - High DV 'Developed Vetting
UNLEASH YOUR POTENTIAL
Everything we do is built on a commitment to do the right thing for our customers, our people and our community. Our mission and our values guide the way we do business. The foundations of our Leidos culture are our Values, Beliefs and Expectations by which we select, recognise and reward employees. They create the environment that drives us toward our mission.
Are you ready for your next challenge?
You will provide a crucial role in Core Services, conducting complex fault rectification of incidents, support Problem Management, Continual Service Improvement (CSI), and occasional Change Request (CR) work on IT Systems supporting key National Security outputs.
3rd Line Network Engineers conduct reactive and proactive maintenance, primarily on High Side systems, but may occasionally be required to support other lower classification systems that Leidos manage. These systems are highly utilised with many active users who operate at varying security levels.
3rd Line Network Engineers are responsible for responding to escalations from 2nd Line Engineers as well as other Resolver Groups and conduct advanced troubleshooting to diagnose and rectify issues as they arise.
3rd Line Network Engineers will be able to develop technical solutions to complex issues and problems as well as possess the ability to liaise with stakeholders at all levels of seniority, including the customer. Adherence to resolving issues and problems within SLA levels and ensuring KPI’s are met is also required.
Essential Requirement
Software Defined Networking experience with VMWare NSX.
3rd Line Network Engineerswill;
Have a thorough and demonstrable understanding of Cisco Enterprise LAN environments at 3rd line support level including, deployment, administration and troubleshooting. Ideally to a CCNP and CCDP level.
Focus on Secure LAN environments including security boundaries and rulesets.
Have a good understanding of WAN connectivity and routing protocols also with experience and understanding of the implementation, configuration and management of virtual and physical networking solutions.
Have hands on experience in troubleshooting Layer 2/3 switching and routing.
Have hands on experience in configuring and troubleshooting VPC, VDC, STP, BGP, OSPF and other key mainstream protocols.
Have hands on experience in configuring and troubleshooting Sidewinders and ASAv firewalls with a Platform focus of: ISR, 6800, 3750, 3850 series.
Have hands on experience in configuring and troubleshooting Fortigate, Sonicwall, Palo Alto, ForcePoint, ASAv and Juniper Firewalls.
Possess excellent communications skills, organisational skills and be independent and comfortable with autonomous working.
Have the ability to tackle complex problems and incidents.
Have experience in ITIL ICT service delivery on critical infrastructure.
Have experience of working under pressure to meet deadlines while handling multiple priorities.
Be experienced in patch management including analysis and deployment.
Key Duties
System Support & Ticket resolution - Utilising technical expertise to ensure that the Core Network estate is kept online and running smoothly and that Incidents are dealt with in a timely manner IAW with KPI/SLA.
Problem Resolution- Work with other resolver groups, original manufacturers, Users and suppliers to perform root cause analysis, providing technical solutions to complex problems.
Maintenance - Responsible for completing the and recording Periodic maintenance of all systems Utilising Periodic Preventative Maintenance (PPM) and routine upgrading activities to stay ahead of obsolescence issues.
Documentation - Maintain and create documentation of system configuration changes. As well as accurately recording work in SD+.
Resource Movement - Assist in the configuration, installation, and deployment of infrastructure components.
Participation in Projects - Engage in infrastructure-related projects and CR’s contributing to implementation build, testing phases.
Key Competencies:
Communications - Verbal, written including technical documentation.
Collaboration - Working with other SME’s, Users & Resolver groups to ensure efficiency.
Adaptability and flexibility - Able to change focus under changing situations.
Technical expertise - Ability to troubleshoot and fault rectification variety of issues.
Attention to detail - Including written and work carried out.
Customer service - excellence.
Teamwork - Build effective internal and external relationships.
What we do for you:
At Leidos we are PASSIONATE about customer success, UNITED as a team and INSPIRED to make a difference. We offer meaningful and engaging careers, a collaborative culture, and support for your career goals, all while nurturing a healthy work-life balance.
We provide an employment package that attracts, develops and retains only the best in talent. Our reward scheme includes:
Contributory Pension Scheme
Private Medical Insurance
33 days Annual Leave (including public and privilege holidays)
Access to Flexible benefits (including life assurance, health schemes, gym memberships, annual buy and sell holidays and a cycle to work scheme)
Flexi-TIme
Commitment to Diversity:
We welcome applications from every part of the community and are committed to a truly diverse and inclusive culture. We foster a sense of belonging, welcoming all perspectives and contributions, and providing equal access to opportunities and resources for everyone. If you have a disability or need any reasonable adjustments during the application and selection stages please let us know, and we will respond in a way that best fits your needs.
Who We Are:
Leidos UK & EUROPE - we work to make the world safer, healthier, and more efficient through technology, engineering and science.
Leidos is a growing company delivering innovative technology and solutions focused on safeguarding critical capabilities and transformation in frontline services, our work in the United Kingdom includes addressing some of the most complex problems in defence, healthcare, government, safety and security, and transportation.
What Makes Us Different:
Purpose: you can use your passion and abilities at Leidos to keep the people you care about safe. We are at the forefront of machine learning, AI, cyber security and solutions. Using your skills in the technology frontline by helping to build a safer world. You can inspire change.
Collaboration: having flexibility to do your job is one of our core benefits, enabling you to become part of our extraordinary team. We have been empowering our people to work flexibly for years. Whether you work from home, the office or on customer sites, we will give you the digital tools and the flexibility to work smarter and align your needs and ours.
People: Leidos empowers people from every background to be themselves and gives you the tools to learn new skills by enabling growth whilst developing. We believe that extraordinary people need opportunities to grow, to be inspired and to inspire others. At Leidos, we invest in technical academies, career rotations and a career development plans that enhance your future.
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:
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:
£44,700.00-£57,300.00The Leidos pay range for this job level is a general guideline only and 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.