Senior On-Prem systems Administrator - Remote, Guelph

Job Summary We are seeking an experienced Senior On-Premises Systems Administrator to oversee, secure, and modernize our core enterprise infrastructure. This role centers heavily on mastering our on-premises footprint specifically advanced Active Directory management, Windows Server 2025 infrastructure, database administration, and specialized networking while smoothly bridging the gap to our hybrid Microsoft 365 and Intune environment. The ideal candidate is a seasoned administrator who thrives on maintaining high-availability local systems, robust security protocols, and reliable corporate communication pipelines.Responsibilities Active Directory&Identity Lifecycle: Architect and manage on-premises Active Directory (AD), including complex Group Policy Object (GPO) design, implementation, and cross-site replication topologies. Next-Gen Windows Infrastructure: Oversee the deployment, upgrading, and maintenance of core server infrastructure, specifically utilizing Windows Server 2025 features and replication services.Database&Certificate Management: Administer and optimize Microsoft SQL Server environments. Manage and maintain the internal Public Key Infrastructure (PKI) and Certificate Authority (CA) to ensure secure system communications. Networking&Edge Security: Configure, monitor, and troubleshoot advanced networking components, enterprise firewalls, secure VPNs, and essential network services (DNS, DHCP). Unified Communications: Manage, provision, and troubleshoot the enterprise Microsoft Teams Phone System, including direct routing, user provisioning, and call queue management.Hybrid&Cloud Endpoint Modernization: Maintain the hybrid identity bridge (Microsoft Entra Connect) and manage modern endpoint deployment and compliance policies via Microsoft Intune and M365 suite services. Automation&Scripting: Develop and maintain advanced PowerShell scripts to automate routine Active Directory modifications, server provisioning, and system auditing. Documentation&Compliance: Create and maintain comprehensive documentation regarding GPO structures, network topology, firewall rules, and disaster recovery procedures. Skills Expert-Level Windows Administration: Deep technical knowledge of Windows Server (including Windows Server 2025), Active Directory Architecture, GPO management, and multi-site replication.Core Infrastructure Services: Proven experience managing Microsoft SQL Server and deploying/maintaining an enterprise Certificate Authority (CA). Networking&Security: Strong proficiency in computer networking, firewall configuration, secure VPN setups, and routing protocols. Telephony&Collaboration: Hands-on experience administering Teams Phone Systems, enterprise voice routing, and associated hardware/software components. Hybrid Ecosystems: Practical experience with Microsoft 365 administration, modern endpoint management via Microsoft Intune, and hybrid identity environments.Automation: Advanced scripting proficiency in PowerShell for infrastructure automation and systems administration. Problem-Solving&Grit: Exceptional troubleshooting skills with a proactive approach to system security, data integrity, and local high-availability infrastructure.