Job Description System Administrator Up to £55,000 | Permanent | Farnborough (hybrid flexibility) National Security & Defence | Security Clearances required prior to start Are you a system admin with Windows and Linux experience and want to keep critical systems reliable, secure, and up to date across multiple environments. Here, you’ll own monitoring, patching, and hardening workflows that underpin a high-profile programme. This is working for a growing defence consultancy with extensive growth secured for the next few years, with lots of projects in the Defence Industry. Core Focus Proactively monitor and triage alerts (Elastic Maintain resilient network connectivity across the estate Run vulnerability assessments (Nessus) and action SOC outputs Implement firewall upgrades and configuration changes Manage WSUS for controlled Windows patch deployments Maintain Linux repositories and oversee patching cycles (pre-prod → prod) Essentials Proven System Administration in secure/enterprise environments Hands-on with Linux and Windows Server Patching at scale (WSUS, Linux repos) and firewall management Understanding of network protocols and core cyber security principles Familiar with Elastic monitoring, Nessus, and SOC workflows If you take pride in clean operational execution and secure-by-default systems, this is a solid fit. There are good corporate benefits and lots of career growth and opportunities going forward. Successful applicants will be required to be security cleared prior to appointment.