Configure and maintain the organization's internal computer network.Manage network security tools, e.g., firewall, anti-virus and intrusion detection systems.Identify, troubleshoot, solve and document network connectivity and performance issues.Install and support hard-line telephones and other networked telecommunication devices.Monitor network performance and optimize the network for optimal speed and availability.Install, configure and maintain network hardware, for example, Cisco routers and switches.Deploy, configure and upgrade network software, such as, enterprise antivirus or diagnostics programs.Implement and maintain emergency backup and restore systems for mission-critical network servers.Network administrators regulate user access to sensitive files to protect against internal security breaches.In smaller companies, network administrators are often responsible for end-user desktop support, and the maintenance of servers and other networked devices.