A load balancer is an Internet appliance designed to distribute workload across multiple servers or network links to optimize resource use, maximize throughput, minimize response time, and avoid overload on any one of the servers. This is fundamental for students to understand because managing server traffic and maintaining service availability are key aspects of network administration. Internet appliances like Unified Threat Management (UTM) devices focus on security functions, spam gateways specialize in filtering unwanted emails, and proxy servers are responsible for forwarding client requests to other servers while possibly hiding the client's true identity.