Senior Network Security Engineer – Cisco ACI & SD-WAN

Our client, a leading organization in the energy infrastructure sector, is seeking a Senior Network Security Engineer to oversee the security and operations of a multi-site network environment. The role involves managing complex IT and OT systems to ensure 24/7 service availability while supporting large-scale connectivity and modernization projects across Europe.

• Manage and secure network operations within both IT and OT environments to ensure continuous service availability.
• Prepare and execute technical changes with high diligence to maintain stability across critical systems.
• Design and deploy connectivity solutions for data centers and cloud-integrated infrastructures.
• Maintain and modernize wide-area network (WAN) architectures and enterprise routing protocols.
• Collaborate with cross-functional ICT teams to support network services across multiple European locations.
• Implement and manage network security frameworks including firewalls and access control systems.

• 8+ years of experience in network engineering with a focus on Cisco technologies.
• Advanced knowledge of routing and switching protocols including OSPF, ISIS, MP-BGP, and MST.
• Proven experience with Cisco ACI, Cisco SD-WAN, and Cisco Wireless solutions.
• Hands-on experience with firewall technologies from Checkpoint and Palo Alto.
• Expertise in cloud networking specifically within Microsoft Azure environments.
• Experience using Python or Ansible for network automation and orchestration.
• Knowledge of backend monitoring and security tools such as Zabbix, Elastic, ISE, and NAC.
• Willingness to participate in a standby rotation (maximum one week in four).
• Proactive team player with the ability to work independently in a complex technical environment.
• You are fluent in English with proficient knowledge of Dutch or French.

Nice to Haves

• Familiarity with TACACS and RADIUS servers.

• Start date: 28/09/2026
• Duration: 1 year (renewable)
• Work regime: Full-time
• Location: Brussels
• Working model: Hybrid (initial 3 months full-time onsite, followed by 3 days per week onsite)
• Contract: open to both permanent employees and freelancers