Which command is used to perform network throughput tests?

The command used to perform network throughput tests is iperf. This tool is specifically designed to measure the bandwidth and performance of a network connection by transmitting data between two hosts and calculating how much data can be sent over a specified period. It provides detailed statistics on the transmission rate, which is crucial for assessing the performance of network links.

Other options serve different purposes: ping is primarily used for checking the reachability of a host on an IP network and measuring the round-trip time for messages sent to the destination; traceroute helps in determining the path taken by packets to reach a network destination and can assist in diagnosing routing issues; and mtr, which combines the features of ping and traceroute, provides information on the route packets take and the latency for each hop but does not specifically focus on throughput measurements. Thus, iperf stands out as the dedicated tool for assessing network throughput, making it the correct choice.