Senior IT Security & Infrastructure Engineer

About the role The Senior IT Security & Infrastructure Engineer is responsible for ensuring the reliability, security, performance and day-to-day operation of the company's IT infrastructure, networks, systems and end-user technology environment. The role serves as the senior technical escalation point for complex network, infrastructure, cybersecurity, Microsoft 365 and end-user issues while providing hands-on leadership to IT Support team. The incumbent is expected to possess strong practical knowledge in enterprise network engineering and cybersecurity, independently diagnose complex technical problems, perform root-cause analysis, implement appropriate solutions and strengthen the company's overall IT resilience and security posture. This is a hands-on technical leadership position requiring the successful candidate to lead by example, remain technically involved and progressively develop the capability of the IT Support team. Key responsibilities Team Leadership and IT Service Management Lead, coach and provide technical guidance to IT Support team members. Allocate and prioritise daily support activities based on business impact, urgency and technical complexity. Serve as the primary escalation point for complex infrastructure, network and cybersecurity issues. Review unresolved and recurring incidents and ensure root-cause investigation and corrective action. Establish and continuously improve IT SOPs, troubleshooting guides, checklists and technical documentation. Develop junior team members through coaching, knowledge transfer and structured problem-solving. Ensure timely communication to users and management during major incidents or service disruptions. Network Engineering and Operations Take technical ownership of LAN/WAN infrastructure, Layer 2/Layer 3 switching, enterprise Wi-Fi, routers, firewalls, VPN connectivity, network segmentation, DNS, DHCP, internet and site-to-site connectivity. Configure and troubleshoot TCP/IP, IPv4 subnetting, VLANs, inter-VLAN routing, switching, trunking, spanning tree, DNS, DHCP, NAT, VPN and QoS. Configure and troubleshoot managed switches, firewalls, routers and wireless access points/controllers. Design and maintain appropriate VLAN and network segmentation for users, servers, infrastructure, wireless networks and other connected devices. Monitor network availability, utilisation, capacity, latency and performance. Diagnose complex routing, switching, DNS, DHCP, Wi-Fi, VPN and firewall-policy issues. Perform packet capture and traffic analysis using tools such as Wireshark. Review network logs, syslog, SNMP alerts and firewall events to identify performance and security issues. Maintain physical and logical network diagrams, IP-address records, device configurations and firewall-rule documentation. Maintain backups of critical network-device configurations. Plan and execute network upgrades, firmware updates and configuration changes with testing and rollback plans. Work with ISPs, network vendors and technology partners to resolve complex issues. Cybersecurity Operations Configure and maintain firewall rules, network-security policies, network segmentation and secure remote-access controls. Administer and monitor endpoint security tools such as Bitdefender. Review security alerts and investigate suspicious endpoint, network, user or system behaviour. Support vulnerability assessment, risk-based remediation, patching and compliance activities. Support Microsoft Entra ID and Microsoft 365 identity and access management. Apply least-privilege, multifactor authentication and controlled administrative-access principles. Periodically review privileged accounts, access permissions and obsolete accounts. Support security-incident investigation, containment, evidence preservation and root-cause analysis. Track security remediation and corrective actions through completion. Work with the Cyber-Security Engineer and external specialists where deeper expertise is required. Microsoft 365 and Identity Administration Administer Microsoft 365 Admin Center, Microsoft Entra ID, Teams, SharePoint Online, OneDrive and Exchange-related services where applicable. Create, modify and decommission corporate user accounts, groups, licences and permissions. Support employee onboarding, internal transfers and offboarding. Review administrative privileges and access rights. Troubleshoot Microsoft 365 authentication, access and collaboration issues. Maintain appropriate records for account and access administration. Server, Cloud and Infrastructure Management Manage and support Windows Servers, Azure-based servers and services, Virtual Machines, NAS/storage, identity services, DNS/DHCP, backup infrastructure, printers, PBX/VoIP, CCTV/NVR, door-access systems and network equipment. Monitor infrastructure availability, capacity and performance. Troubleshoot server, storage and infrastructure issues and coordinate preventive maintenance. Support infrastructure upgrades, migrations and replacements. Maintain system configurations and recovery documentation. Ensure critical infrastructure is appropriately backed up. Backup, Disaster Recovery and Business Continuity Coordinate scheduled backup activities and investigate backup failures. Periodically validate recoverability of critical systems and data. Maintain infrastructure recovery documentation. Support Disaster Recovery and Business Continuity planning and testing. What we're looking for Diploma or Bachelor's degree in Information Technology, Computer Science, Information Systems, Network Engineering, Cybersecurity or a related discipline. Preferably at least 5 years of hands-on experience in IT/ICT infrastructure, network engineering, systems administration, cybersecurity or technical support. Demonstrated experience troubleshooting complex enterprise network and infrastructure issues. Hands-on experience administering enterprise switches, firewalls, Wi-Fi and VPN environments. Strong experience with Microsoft 365, Microsoft Entra ID and Windows-based infrastructure. Practical experience in endpoint security, vulnerability remediation, patching and backup operations. Experience performing technical root-cause analysis and delivering infrastructure or security projects. Prior experience leading, mentoring or technically supervising junior IT engineers is strongly preferred.