Administrateur Systèmes & Réseaux H/F

ABOUT ALTA ARES Alta Ares is an air defense Neoprime. We build AI-guided interceptors to counter drones and cruise missiles, along with the software platform that powers them. Our customers are NATO-aligned militaries and defense institutions, and our systems are regularly deployed during live exercises and operational demonstrations across Europe, the Middle East, and Asia. Founded in 2024, we have grown to 90 people, raised over $60M, and increased revenue 40× this year. We are now entering a new phase of international expansion, industrial scaling, fundraising, and product development. Role & Mission - Administer and evolve Alta Ares' IT infrastructure across Windows, macOS and Linux environments, including cloud services (GCP, Scaleway). - Maintain and secure enterprise networks, including LAN/Wi-Fi, VLANs, VPNs, DNS/DHCP, firewalls, network segmentation and 802.1X/NAC. - Manage identity and access systems, including RBAC, MFA, SSO, conditional access, and Zero Trust principles. - Administer endpoint and mobile device management solutions, including MDM/MAM/RMM, NinjaOne and Apple Business Manager. - Operate and improve cybersecurity tools, including EDR/XDR, vulnerability management, log monitoring and incident response. - Ensure backup reliability, conduct restoration tests and contribute to business continuity and disaster recovery planning. - Monitor infrastructure performance, troubleshoot complex incidents and coordinate external IT service providers. - Automate recurring IT operations using PowerShell, Bash and APIs, while maintaining clear and up-to-date technical documentation. - Collaborate with the IT Support Engineer and technical teams to strengthen IT operations, security and infrastructure scalability. Candidate Profile - 3 to 5 years of experience in systems and network administration, ideally in a growing or technically demanding environment. - Strong knowledge of Windows, Linux and macOS systems, TCP/IP networking, cloud infrastructure and enterprise network environments. - Experience with IAM, endpoint management, cybersecurity tools and infrastructure monitoring. - Familiarity with Google Workspace and/or Microsoft 365, EDR/XDR solutions and IT automation. - Proficiency in scripting with PowerShell, Bash or APIs to automate operational tasks. - Autonomous, rigorous and methodical, with strong troubleshooting skills and a security-first mindset. - Ability to take ownership of infrastructure projects and contribute to the structuring and continuous improvement of IT operations. - Degree in IT, systems and networks (Bac+2 to Bac+5) or equivalent practical experience.