Key duties include managing Linux, Unix, and Windows servers, user access, system security, patching, performance optimization, backup and disaster recovery, as well as troubleshooting networking technologies such as TCP, IP, DNS, DHCP, VPNs, firewalls, and VLANs. Additionally, the role requires developing automation through scripting, supporting CI/CD and DevOps processes, and maintaining technical documentation, runbooks, and architectural diagrams to improve operational efficiency and reliability.