Senior Network Engineer

Are you an experienced Network Engineer ready to take ownership of complex, secure network environments?

Sopra Steria is delivering a unique solution from the ground up for the Defence sector, integrating infrastructure and applications within highly secure, mission-critical environments. This is an opportunity to make a genuine impact, contribute to complex technical solutions, and work on a nationally significant programme that few organisations can offer exposure to.

For someone motivated by purpose, scale, and technical complexity, this role offers the chance to see your work directly contribute to outcomes that really matter.

This role requires full-time, on-site working in Hertfordshire.

What you will be doing:

• Deliver expert L2/L3 support for a complex, multi-site enterprise network, resolving incidents and minimising service disruption.
• Configure and maintain Cisco network infrastructure, including switches, routers, and core connectivity services.
• Support and optimise F5 application delivery and load balancing platforms to ensure availability, performance, and resilience.
• Administer Fortinet firewalls and security services, including policy management, VPN configuration, and security compliance changes.
• Execute planned network changes, upgrades, and site deployments while adhering to change control and security standards.
• Maintain low-level designs, technical documentation, and operational procedures, while supporting wider project delivery and continuous improvement activities.

What you will bring:

• Strong knowledge of Cisco routing and switching.
• Experience with Cisco firewalls, including Firepower.
• Experience with Fortinet technologies.
• Active MoD DV clearance, or active SC clearance with willingness to undergo DV clearance.
• Strong troubleshooting skills across complex enterprise network environments.
• Ability to work effectively in secure, mission-critical, or regulated environments.

It would be great if you had

• Exposure to F5 and wider network security or DDoS-related tooling.
• Cisco certifications, such as CCNA or CCNP.
• Experience supporting multi-site Defence, government, or secure enterprise networks.

If you are interested in this role but not sure if your skills and experience are exactly what we’re looking for, please do apply, we’d love to hear from you!

Employment Type: Permanent

Location: Hertfordshire

Security Clearance Level: Eligible for Developed Vetting (DV)

Internal Recruiter: Josh

Salary: Competitive, based on experience

Benefits: 25 days annual leave with the choice to buy extra days, life assurance, and 6% pension

If you’re interested and need to work flexibly, we encourage you to apply and talk to us about what might be possible.

Loved reading about this job and want to know more about us?

Sopra Steria’s Aerospace, Defence and Security business designs, develops and deploys digital solutions to Central Government clients. The work we do makes a real difference to the client’s goal of National Security, and we operate in a unique and privileged environment. We are given time for professional development activities, and we coach and mentor our colleagues, sharing knowledge and learning from each other. We foster a culture in which employees feel valued and supported and have pride in their work for the customer, delivering outstanding rates of customer satisfaction in the UK’s most complex safety- and security-critical markets.