Job Description
We are seeking a highly experienced Senior System Administrator to support and evolve our hybrid on‑premises and cloud infrastructure in a Geneva‑based, international environment. This role requires strong expertise in Microsoft technologies, Azure, identity and security services, and virtualization, with a high standard of reliability and professionalism.
The position plays a critical role in ensuring availability, security, and compliance of core IT services supporting business‑critical operations.
Key Responsibilities
* Design, implement, and maintain Windows Server environments (on‑premises and cloud)
* Administer and optimize Microsoft Azure infrastructure and services
* Manage and support Microsoft 365 / Office 365, including Exchange Online and collaboration services
* Administer Microsoft Entra ID (Azure AD), including hybrid identity, synchronization, conditional access, and authentication policies
* Manage Active Directory, ADFS, DNS, and core identity services
* Operate and maintain VMware virtualization platforms
* Administer Microsoft Exchange environments (on‑premises, hybrid, and/or cloud)
* Manage Public Key Infrastructure (PKI), including certificate authorities and trust models
* Ensure certificate lifecycle management (TLS/SSL, authentication, encryption) across servers, applications, and services
* Ensure high availability, backup, disaster recovery, monitoring, and capacity planning
* Troubleshoot complex infrastructure, identity, and authentication issues
* Apply security best practices in line with Swiss and international compliance requirements
* Participate in audits, risk assessments, and documentation efforts
* Collaborate closely with internal IT teams and international stakeholders
* Maintain clear technical documentation and operational procedures
* Provide technical leadership and mentoring to less experienced administrators
Qualifications
Required Technical Skills & Experience
* Several years of experience as a Senior System Administrator in an enterprise environment
* Strong hands‑on expertise in:
o Microsoft Azure
o Microsoft Entra ID (Azure AD)
o Microsoft 365 / Office 365
o Windows Server
o VMware / Vsphere
o Active Directory & ADFS
o DNS, DHCP
o Microsoft Exchange
o PKI and certificate management
* Proven experience with hybrid (on‑premises and cloud) infrastructures
* Solid understanding of identity, authentication, encryption, and security principles
* Experience with PowerShell and automation is highly valued
Soft Skills & Personal Attributes
* Open‑minded – comfortable working in a multicultural, international environment
* Reliable – trusted to operate and support critical systems
* Flexible – adaptable to changing priorities, projects, and operational needs
* Structured and methodical approach to problem‑solving
* Strong communication skills in technical and business contexts
* Team player with a professional and service‑oriented mindset
Languages
* English: professional working proficiency (required)
* French: working knowledge is a strong advantage
Nice to Have
* Microsoft / Azure certifications
* Experience in regulated environments (finance, trading, healthcare, international organizations)
* Familiarity with Swiss data protection and security standards
* Experience supporting international or multi‑site infrastructures
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