What is the main use of the traceroute tool?

The primary function of the traceroute tool is to trace the path that packets take through a network to reach a destination. This tool sends out a series of packets, typically using ICMP (Internet Control Message Protocol) echo requests, and manipulates the Time to Live (TTL) field in the packet headers. As each packet travels through the network, routers decrement the TTL value. When the TTL reaches zero, the router discards the packet and sends back an ICMP Time Exceeded message. By incrementing the TTL value with each set of packets sent, traceroute can identify each hop along the route to the destination, including the IP address of each router encountered.

This capability allows network administrators and engineers to pinpoint where delays or issues may be occurring in the communications path, offering valuable insights for troubleshooting connectivity problems or optimizing network performance. Understanding the latency at each hop helps in diagnosing where a bottleneck may be occurring.

The other options, while related to networking, do not encapsulate the primary function of the traceroute tool. Displaying routing tables pertains to understanding the routing decisions made by a router, identifying open ports involves security assessments of devices, and pinging multiple destinations pertains more to availability checks rather than tracing packet routes.