Mobileum - Senior System Administrator - Windows Server

Position : Senior System Administrator

Job Summary

We are seeking a highly experienced and self-motivated Senior System Administrator with a strong background in Windows Server Administration, Microsoft 365, Active Directory, Linux, networking, and security infrastructure. This individual will play a key role in managing enterprise-level systems, securing digital environments, and ensuring optimal IT performance.

The ideal candidate is up-to-date with the latest industry trends, capable of performing internal assessments, identifying gaps, and implementing robust solutions across a hybrid IT landscape.

Key Responsibilities

Windows & Server Administration :

• Manage, monitor, and maintain Windows Server infrastructure, including patching, performance tuning, and configuration.
• Provide expert-level support for Windows-based systems, ensuring high availability and security.
  
  

Microsoft Office 365 & Azure AD

• Administer and support Microsoft 365 services including Exchange Online, SharePoint, Teams, OneDrive, and Security & Compliance Center.
• Manage hybrid identity using Azure AD, SSO, and directory synchronization.
• Implement and monitor policies using Microsoft Purview, DLP, and conditional access.
  
  

Active Directory & Identity Management

• Design, maintain, and secure on-premises Active Directory infrastructure.
• Perform regular audits, GPO configuration, OU structuring, and delegation of permissions.
  
  

Email Security & Awareness Training

• Deploy and manage email security solutions targeting phishing, spoofing, spam, and malware.
• Conduct phishing simulation campaigns and user awareness training programs.
• Evaluate and recommend security tools and protocols to protect organizational communication.
  
  

Firewall & Network Security

• Configure and maintain FortiGate Firewalls, including VPN, policies, routing, and IPS/IDS.
• Monitor and analyze network traffic to identify and respond to threats and performance issues.
  
  

Linux & Cross-platform Support

• Provide support for Linux servers (Debian, RHEL, CentOS), focusing on scripting, updates, and integration with AD.
• Assist with cross-platform compatibility and troubleshooting.
  
  

Backup & Recovery

• Implement and manage enterprise backup solutions such as Barracuda and Commvault.
• Define recovery point objectives (RPOs) and recovery time objectives (RTOs) for business continuity.
  
  

Domain & Web Hosting

• Manage domain registrations, DNS configurations, SSL certificates, and hosting platforms.
• Liaise with hosting providers and ensure uptime and security of public-facing web services.
  
  

End User Management

• End user computing and handle day to day operations related to Laptop, Desktop and Server Infra
• Provide support to VIP users and Senior Executives independently
• Manage Server, Laptop, Desktop Inventory
  
  

Required Skills & Qualifications

• Advanced knowledge on RHEL/Debian Operating System
• Advanced knowledge of Windows Server 2012-2022, Office 365, Azure AD, and email security tools.
• Hands on experience with FortiGate firewall and switches configuration and administration.
• Hands on experience on networking infra.
• Familiarity with industry best practices for cyber security and compliance.
• Knowledge of ITIL principles and implementation.
• Up to date with current technologies, trends, and security threats.
  
  

Soft Skills

• Strong presentation skills and the ability to communicate complex technical concepts to non-technical stakeholders.
• Excellent reporting and documentation skills.
• Proactive, self-driven, and capable of identifying and closing operational gaps independently.
• Strong interpersonal and collaborative skills; able to work across teams and with vendors.
• Ability to manage time efficiently in a dynamic work environment.
  
  

Preferred Certifications

• Microsoft Certified : Azure Administrator Associate / Microsoft 365 Certified
• ITIL Foundation Certification
• RHEL Certification is preferred
  
  

Educational Qualification : Bachelor's Degree in Computer Science, Information Technology, or a related field.

Work Experience : 12+ years of proven hands-on experience in system administration and infrastructure support.

Location : Cupertino, California, USA

(ref:hirist.tech)