Senior Network Engineer – Secure Defence Enterprise Networking

Thorn SDS; Corsham; On-site; GBP 65,000 - 75,000; Full time

Benefits offered by this job

25 days leave

Pension contributions

Group Life Insurance

Wellbeing services

Referral scheme

Training & certifications

Defence programme exposure

Enterprise networking tech exposure

Job summary

Thorn SDS in Corsham is seeking a Senior Network Engineer to design, maintain and optimise enterprise network infrastructure within a high‑security UK defence programme. You will deliver 2nd/3rd line support, tackle complex networking challenges and support secure deployments across fixed and deployable environments.

The role requires onsite work in Corsham with strong analytical, troubleshooting and communication skills, plus experience in enterprise routing/switching, Cisco tech, firewalls and

Qualifications

• Proven experience in enterprise LAN/WAN design, deployment and support.
• Strong knowledge of routing, switching and network security practices.
• Experience with firewalls, VPNs, and secure remote connectivity in regulated environments.
• Familiarity with VMware NSX or similar SDN tech is desirable.
• Ability to monitor, troubleshoot and optimize complex network infrastructure.
• Understanding of Layer 2/3/4 networking and performance analysis.
• Experience working in defence, MOD, or security-cleared environments.
• Ability to work onsite in Corsham with strong analytical and communication skills.

Responsibilities

• Provide advanced 2nd and 3rd line support across enterprise network infrastructure.
• Troubleshoot complex network issues and implement infrastructure improvements.
• Support secure deployments across fixed and deployable environments.
• Coordinate with service operations, resolver groups and engineering teams.
• Maintain network resilience and compliance with security policies.
• Support deployments across on‑premises and operational environments.
• Participate in ITIL-aligned incident, problem and change management processes.
• Contribute to the delivery of a deployable IT capability modernization programme.
• Collaborate with cross-functional teams to resolve technical issues.

Skills

Enterprise routing & switching

Cisco networking technologies

Firewalls & VPNs

Network monitoring & troubleshooting

Layer 4 dependencies & performance

Secure, regulations environments

Defence/MOD exposure

Tools

VMware NSX

Job description

Thorn SDS in Corsham is seeking a Senior Network Engineer to design, maintain and optimise enterprise network infrastructure within a high‑security UK defence programme. You will deliver 2nd/3rd line support, tackle complex networking challenges and support secure deployments across fixed and deployable environments.

The role requires onsite work in Corsham with strong analytical, troubleshooting and communication skills, plus experience in enterprise routing/switching, Cisco tech, firewalls and