Senior Network Administrator

Start Date: ASAP

End Date: 30/06/2026

Location: Brussels

Work Regime: Full-time, 2 days on-site

Job Description:

We are looking for a skilled and motivated Senior Network Administrator to ensure the design, deployment, security, and optimization of the network infrastructure within a hybrid environment. The Senior Network Administrator plays a key role in the transition toward a state-of-the-art infrastructure, aligned with modern technological constraints and the evolving needs of the organization. In this role, you will collaborate closely with experts in telecommunications interception, infrastructure engineering, and IT operations.

Responsibilities:

• Network Architecture & Infrastructure Management:
  • Design, deploy, and manage physical and virtual networks in hybrid environments (on-premise & cloud).
  • Administer, configure, and maintain LAN/WAN/WLAN infrastructures.
  • Participate in the evolution of network architecture based on application and service requirements.
  • Work with infrastructure teams to implement SDN and other virtualized network services.
• Security & Reliability:
  • Ensure the security, resilience, and reliability of network and communication systems.
  • Manage firewalls, VPNs, load balancers, IDS/IPS, and other network security solutions.
  • Define, implement, and maintain network security policies and best practices.
  • Identify vulnerabilities and contribute to mitigation strategies.
• Operations & Troubleshooting:
  • Monitor network performance and proactively detect anomalies.
  • Diagnose and resolve complex connectivity, performance, and configuration issues.
  • Support incident response and ensure timely resolution of critical problems.
  • Maintain and update network documentation, configurations, and operational procedures.
• Project Participation & Collaboration:
  • Contribute to infrastructure and migration projects, including virtualization and modernization initiatives.
  • Work closely with system, security, and telecom experts to ensure solution consistency.
  • Take ownership of assigned tasks, assess risks, and escalate when necessary.
  • Contribute as a team player while being fully capable of working independently.
• Continuous Improvement & Technology Watch:
  • Conduct technology watch and propose improvements aligned with industry trends.
  • Promote continuous improvement approaches and pragmatic, solution-oriented practices.
  • Support knowledge sharing and contribute to internal expertise development.

Required Experience:

• 5–7+ years of experience in network administration, ideally in hybrid or critical environments.
• Strong command of Cisco, Fortinet, or equivalent technologies.
• Excellent knowledge of network protocols and technologies: TCP/IP, VLAN, BGP, OSPF, QoS, MPLS, routing & switching.
• Proven experience with firewalls, VPNs, IDS/IPS, and segmentation strategies.
• Experience with virtualization and modern network technologies: SDN, virtualized network services.
• Familiarity with network monitoring and management tools.

Soft Skills & Professional Qualities:

• Bachelor’s or master’s degree in IT, networking, or equivalent professional experience.
• Strong analytical mindset with a focus on continuous improvement.
• Pragmatic, solution-oriented approach to technical challenges.
• Curious, proactive, and eager to learn new technologies.
• Excellent written and verbal communication skills, able to explain complex topics clearly.
• Discrete, stress-resistant, and reliable in critical environments.
• Ability to work autonomously while contributing effectively to team objectives.
• Fluent in French or Dutch, with a solid understanding of the other language.
• Good command of written and spoken technical English.
• A certification in CCNP, CCIE, NSE, PCNSE, or equivalent is a plus.

Must-Have Skills:

• Cisco firewalls, VPNs, load balancers, IDS/IPS
• Fortinet
• LAN/WAN/WLAN
• MPLS, routing & switching
• Network Administration
• Network Architecture
• SDN
• TCP/IP, VLAN, BGP, OSPF, QoS