Senior Network Infrastructure Engineer - Defence Programme Location: Caerphilly (with travel to client / Ministry of Defence sites as required)Clearance: SC (must hold or be eligible); DV highly desirableSalary: 75,000 + Bonus + Comprehensive Benefits Package About the Role A major Defence programme is seeking a highly skilled Senior Network Infrastructure Engineer to lead the design, implementation and ongoing support of secure, resilient, multi?domain network services. You will work across datacentre networks, secure LAN/WAN, SDN?enabled virtualised environments, and deployed operational sites - ensuring high availability, compliance and adaptability in a mission?critical environment. Key Responsibilities Lead the design, configuration and support of secure multi?site LAN/WAN/SDN infrastructure. Configure and optimise enterprise switching platforms (e.g., Cubic M3X S8G / S24G, Cisco ESS3300?based). Implement routing protocols including BGP, MPLS, VPLS, and HA technologies. Configure firewalls, VPNs, IDS/IPS and boundary protection systems. Support virtualised routing and SD?WAN technologies (Cisco Catalyst 8000V). Act as senior escalation point for complex incidents. Ensure compliance with MOD security standards and Secure by Design principles. Maintain documentation, diagrams and CMDB records. Support accreditation processes (IT Health Checks, CCVAs). Contribute to network automation (Python, Ansible, PowerShell). Identify opportunities for architectural improvement. Essential Experience Extensive multi?site LAN/WAN experience. Advanced configuration skills on Cisco and Cubic platforms. Deep knowledge of BGP, MPLS, VPLS and segmentation. High?availability technologies (HSRP/VRRP equivalents). DNS, DHCP, NAT, IP planning. Experience in secure or Defence?oriented environments. ITIL?based service management. Desirable Experience VMware NSX and SDN, SD?WAN and virtualised routing, VoIP, QoS, SIEM/log analysis tools. Knowledge of JSP, ISO 27001, NIST. Experience leading technical projects. Existing SC/DV clearance. Qualifications Cisco CCNP (required); CCIE desirable. ITIL v4 Foundation or above. Degree in Computer Science, Network Engineering or equivalent experience. Personal Qualities Strong communicator. Analytical problem?solver. Able to mentor and lead. Customer centric and proactive.If you are a Senior Network Infrastructure Engineer with experience working in or with the Defence sector and looking for an exciting new challenge, please send your CV to me today.