Senior Windows & Linux Systems Administrator – Freelance Possible

About the role

We are looking for a Senior Windows & Linux Systems Administrator to develop, maintain and modernise our highly secure IT infrastructure. You will work in a bilingual, multidisciplinary team, with the flexibility to work from home two days a week.

Key responsibilities

• Administer and maintain Windows and Linux server environments.
• Manage core services such as GPO, DNS, DHCP and Active Directory.
• Monitor, optimise and support virtualised platforms (VMware, Proxmox, Hyper‑V).
• Maintain storage platforms, ensuring availability, performance and continuity.
• Implement system security, patching, backups and business‑continuity measures.
• Design and evolve scalable infrastructure architectures.
• Automate tasks using PowerShell, Bash, Python, Perl and Ansible.
• Collaborate with infrastructure, network, security and support teams.
• Diagnose and resolve complex system and software issues.
• Document infrastructure, processes and applications clearly.

Required profile

• Minimum 7 years of senior‑level system administration experience on Windows and Linux.
• Proven expertise in virtualization, storage and security.
• Experience with large‑scale Active Directory migrations.
• Strong scripting knowledge (PowerShell, Bash, Python).
• Understanding of networking, security and identity management.
• Knowledge of Azure or AWS is a plus.
• Bachelor’s or master’s degree in IT or equivalent experience.
• Fluent in French or Dutch and proficient in technical English.
• TOP SECRET security clearance required.

Required skills

• Windows Server
• Linux
• Active Directory
• GPO, DNS, DHCP
• VMware, Proxmox, Hyper‑V
• Storage platforms
• System security & patching
• Backup & business continuity
• PowerShell
• Bash
• Python
• Perl
• Ansible
• Networking fundamentals
• Identity management
• Azure (optional)
• AWS (optional)

What we offer

• Growing Belgian SME with a supportive, fun environment.
• Career development plan and budget for education/certifications.
• Attractive salary and extra‑legal benefits, including a company car.
• Option to work as a freelancer.