Salary: £41,000 - 81,000 per year Requirements: Bachelors degree in Computer Science, Engineering or a related field Professional certifications such as CCNA, CCNP (Security, Firewall specialisms highly valued) Strong background in network administration, switching and routing Excellent troubleshooting skills with the ability to work independently Strong grounding in Active Directory and policy management Knowledge of PAN-OS, SD WAN, Cisco IOS and Extreme Network operating systems Strong understanding of security frameworks and access control models Azure server and related services build, configuration and maintenance Managing backups with Azure / Veeam Client device deployment / patching (Azure Arc / SCCM / WSUS / Intune) Technical knowledge, support, troubleshooting of MS on premises Active Directory infrastructure & related services at an international scale (domain controllers, DFS, GPO, replication) Knowledge of MS Cloud services and their relationships with on-premises infrastructure (EntraID, AD connect) Knowledge of Microsoft 365 architecture, support, and troubleshooting, ideally at an international scale Organisational skills with a track record of mentoring colleagues Experience using diagnostic, monitoring, and network analysis tools Experience working with Windows and Linux Servers (Hyper-V, VMWare) Experience with firewall configuration and management (Palo Alto preferred) Hands-on experience with TCP/IP and routing protocols including BGP and OSPF Responsibilities: Design, deploy, and maintain functional LAN, WLAN, WAN & server infrastructure environments Configure and install network devices, servers, routers and supporting technologies Monitor network integrity, performance, and security across multiple UK sites and assist colleagues in different geographies when required Troubleshoot complex issues escalated by the team and independently resolve them Implement and automate network tasks to improve efficiency Mentor and guide team members on technical topics Develop, test, and oversee security solutions including authentication and disaster recovery Maintain full documentation of all systems, configurations, and processes Identify areas for optimisation related to capacity, scalability, and performance Maintain strong levels of technical security for UK network & server infrastructures, participate in vulnerability assessments, remediations, and security audits Maintain high levels of governance and compliance with both internal and external controls, e.g., Cyber Essentials Plus and ISO27001. Technologies: Active Directory Azure Cloud Cisco Firewall Hyper-V Support LAN Linux Microsoft 365 Network Security TCP/IP VMware Veeam WLAN Windows iOS Office 365 DevOps More: At Expleo, we are dedicated to shaping the future of secure network and server infrastructure across a global organisation. We are currently expanding our UK Infrastructure Team and are looking for a skilled Senior Infrastructure Engineer who thrives in a hands-on technical environment. This role offers high-impact work supporting secure, enterprise-level servers and networks across UK and global teams, with real ownership of architecture, troubleshooting, and continuous improvement initiatives. Join us in a culture built on collaboration, innovation, and professional growth, and be part of a team that values big thinking and challenges the status quo. last updated 14 week of 2026