Senior Security Engineer/Architect - Linux Infrastructure (On-Prem)

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Due to continued growth, we are hiring a Security Engineer/Architect with deep Linux expertise to design and build an on-premise security monitoring capability from the ground up. This is a hands-on engineering and architecture role, not a cloud or Windows role. We are seeking candidates with strong Linux expertise, experience working with SIEM platforms, and an interest in architecting scalable logging and detection solutions rather than solely maintaining existing infrastructure.

Key Responsibilities

• Design and build a centralised logging pipeline: aggregate logs from across the estate into a SIEM/SOC/NOC-style monitoring layer.
• Architect and implement the security monitoring stack using Grafana and Elasticsearch, or an equivalent open-source stack.
• Deploy and manage EDR (Endpoint Detection & Response) across the Linux estate.
• Own SIEM strategy: correlation rules, alerting thresholds, dashboards, and incident triage workflows.
• Maintain and harden pure Linux systems (RHEL derivatives, Debian derivatives); no Windows environments are involved.
• Support on-premise server infrastructure and virtualisation platforms; there is explicitly no cloud or hybrid-cloud scope.
• Manage and configure firewalls, network segmentation, and security rules.
• Lead incident response, root cause analysis, and vulnerability assessments.
• Troubleshoot system-level issues across performance, networking, and configuration.
• Assist with patching, upgrades, and system health checks across the fleet.

Requirements

• Strong hands-on Linux expertise (RHEL, Ubuntu, CentOS, Debian derivatives); Windows experience is not required.
• Proven experience building or architecting a SIEM/logging platform (Grafana, Elasticsearch/ELK stack, or similar).
• Hands-on experience deploying and managing EDR solutions on Linux endpoints.
• Strong background in on-premise infrastructure.
• Working knowledge of firewalls and networking, including host-based, proprietary, and open-source appliances.
• Solid understanding of core networking protocols: TCP/IP, DNS, DHCP, and routing.
• Demonstrated cybersecurity experience: patching, auditing, threat mitigation, and compliance.
• Experience setting up or running a SOC/NOC function, or centralising logs into one.
• Disaster recovery experience covering configuration, storage, and hosts.
• Excellent troubleshooting skills and the ability to work independently at a senior/architect level.

Opportunity

• Hybrid in Dublin.
• Start date: ASAP.