Senior Network Security Engineer / Architect 12 months Contract Role Stelfox has partnered with a leading Dublin-based organisation to recruit an experienced Senior Network Security Engineer / Architect to drive strategic, security-led network transformation initiatives within a business-critical 24x7 operations environment. Location: Dublin, Ireland (Hybrid 3 days on-site, 2 days remote per week) Contract: 12 months Key Responsibilities Lead Cyber Security projects delivering network-related security initiatives across a 24x7 operations network Design and implement enterprise data centre networks using Cisco ACI fabric design Configure and manage Cisco NGFW capabilities including IPS, Security Intelligence, Portscan Detection, and Encrypted Visibility Engine (EVE) Design and optimise application delivery using Citrix Netscaler Implement high availability and disaster recovery strategies Perform firewall lifecycle management (upgrades, policy optimisation, health monitoring) Develop secure network segmentation strategies aligned to zero-trust principles Drive automation using Python, Ansible, and REST APIs Provide third-level technical escalation support Mentor second-line engineers and promote best practice engineering standards Ensure network and security performance monitoring meets SLA requirements Develop and test failover strategies for critical infrastructure components Collaborate closely with application teams, operations, and external stakeholders Required Skills & Qualifications CCIE (Cisco Certified Internetwork Expert) essential CISSP (Certified Information Systems Security Professional) essential Extensive experience in: Security architecture design & implementation Cisco firewalls, ACI networks, LAN/WAN, VPN environments TCP/IP and enterprise network protocols/topologies Threat management & vulnerability assessment Identity & Access Management (I&AM) Network management & administration tooling Strong knowledge of ITIL (Change Management & Continuous Improvement) Excellent communication, documentation, and stakeholder engagement skills ** Live Role - Apply for immediate consideration** If you are interested in this role, please apply or contact in strictest confidence Please note: We have a number of similar positions currently, and in the future, which we would like to discuss with you should you indicate your interest in this role. When we receive your application for this role, we will contact you to advise you of our process for other similar positions. Stelfox is fully compliant with GDPR regulations and you can read more in our privacy policy here: Your shared data will not be disclosed or transferred to a third party data controller or data processor located outside the EEA unless we have obtained your express consent. We look forward to working with you.