Senior Systems and Security Administrator

Job Description Summary: The Senior Systems & Security Administrator is a hands-on role responsible for managing, securing, and supporting a hybrid enterprise IT environment. The position supports Windows Server and Linux/Ubuntu infrastructure, Microsoft 365, Microsoft Entra ID, Active Directory, Exchange Online, AWS, Azure, and Odoo-based business applications. This role manages system and cloud operations, identity and access, system maintenance, patching, monitoring, backup and recovery, vulnerability remediation, Tier 2/3 support, automation, and technical documentation. The administrator independently troubleshoots complex infrastructure issues and applies least-privilege and security best practices. Job Description: Key Responsibilities Systems and Infrastructure Administration Administer Windows Server environments, including Active Directory, DNS, DHCP, Group Policy, file services, patching, and system lifecycle activities. Administer Linux and Ubuntu servers, including users and permissions, services, patching, performance monitoring, log analysis, and troubleshooting. Perform server provisioning, configuration, upgrades, patching, backup validation, recovery testing, and documentation. Monitor system availability, capacity, performance, and backup status, and proactively address issues. Identity, Microsoft 365, and Messaging Administer Active Directory, Microsoft Entra ID, and Microsoft 365 identity services. Manage the full user lifecycle, including account provisioning, access changes, group membership, license assignment, and offboarding. Support hybrid identity environments, including directory synchronization and synchronization troubleshooting. Administer Exchange Online, including user and shared mailboxes, distribution and security groups, mailbox permissions, licensing, and mail flow. Manage Conditional Access, multifactor authentication, enterprise applications, single sign-on, role-based access, and privileged access. Conduct periodic reviews of user accounts, group memberships, licenses, and access permissions. Cloud and Business Application Operations Administer AWS environments, including compute, networking, identity and access, security groups, DNS, load balancing, storage, monitoring, and database services. Support Azure virtual machines, identity services, networking, storage, monitoring, and security controls. Maintain least-privilege access, cloud identity controls, firewall rules, security configurations, and monitoring. Support Odoo environments, including Linux hosting, PostgreSQL connectivity, application availability, logs, backups, and troubleshooting. Collaborate with Odoo developers and business stakeholders on deployments, integrations, scheduled jobs, performance issues, and access requests. Participate in cloud migration, modernization, automation, and infrastructure improvement initiatives. Security and Maintenance Maintain Windows, Linux/Ubuntu, cloud, and business…